file size required to upload to alamy

[Sonia Mills]

Hello 

I am new to Alamy, I would like clarification of what file size to upload, I shoot in raw and can save to Jpeg but  i am confused as to the file size. Thank you 

Sonia

[spacecadet]

File size depends on the content.

There's no reason not to submit at native size, but minimum image size is 17MB, or just over 3000x2000 assuming you don't crop. I use 3250px long side as a minimum if downsizing.

Edited October 8, 2018 by spacecadet

[Jill Morgan]

The minimum size confuses many people. The 17MB minimum is related to your RAW file size just before you turn it in to a jpeg.  Jpegs can vary widely in sizes depending on the content of the image.  I have submitted jpegs from 3 - 15MB.

 

Just remember that you need a 6 megapixel camera minimum.  And as Mark said, if you do 3000x2000 minimum then you will be all right. Or any combo that comes out to 6 megapixels.

 

Jill

[Starsphinx]

I do sometimes wonder if Alamy keeps the size confusion as a possible method of weeding out non-serious potential contributors.  I know when I first looked at Alamy a couple of years ago I did not sign up because I tend to crop my images and like many, I thought the 17mb minimum referred to the compressed jpeg size and very few of my images made that. I am actually glad I was put off initially - I believe the quality of my work has improved seriously since then and I pay far more attention to requirements.

[spacecadet]

3 minutes ago, Starsphinx said:

 confusion

Actually the guidance is quite explicit. Quote, my italics:

File size of over 17MB (when uncompressed/open)
Your JPEG file is likely to have a compressed size of 3-5MB. Opening a JPEG in an image program such as Adobe Photoshop will show you the uncompressed/open file size.

[Starsphinx]

1 minute ago, spacecadet said:

Actually the guidance is quite explicit. Quote, my italics:

File size of over 17MB (when uncompressed/open)
Your JPEG file is likely to have a compressed size of 3-5MB. Opening a JPEG in an image program such as Adobe Photoshop will show you the uncompressed/open file size.

I know the guidance is specific, however, evidence indicates large numbers of people still get confused - I have only been here a few months and have seen multiple threads and posts like this one.  I submitted my first three images only after going repeatedly through the guidelines to work out what they actually mean - when I was newer and much less experienced I skim read them, did not understand them and did not submit any images being convinced I was not up to scratch through size alone.  I suspect a reasonable number of people do the same thing and hence the filter effect.  I now know I would have passed on size - but on quite a few images failed QC on other things because I was way less rigorous with myself.  That I did not submit, went away, improved some, is a good thing - for both Alamy and myself.

It would be a very quick easy thing for Alamy to change its guidance to the "3000px minimum" that is so often the answer to this question on this forum - so them no doing so may have a reason behind it.

[spacecadet]

Just quoting 3000 doesn't allow for the different aspect ratio a cropped image may have, of course.

I don't remember being in any confusion about image size versus file size, but I didn't submit until I'd been taking digital photographs for a few years. So perhaps I just did more homework.

[M.Chapman]

On 08/10/2018 at 16:37, Sonia Mills said:

Hello 

I am new to Alamy, I would like clarification of what file size to upload, I shoot in raw and can save to Jpeg but  i am confused as to the file size. Thank you 

Sonia

 

17MB is the minimum uncompressed 8 bit image size required by Alamy. This means the uncompressed image must contain at least 17 MegaBytes (=17,825,792 bytes) of 8 bit image data. Since each pixel is stored using 3 bytes of data (1 byte each for Red, Green and Blue channels) the minimum number of pixels required by Alamy equates to 17,825,792/3 = 5,941,930 pixels

 

So, as a useful guide, just make sure your image contains at least 6 million pixels, and you'll be OK, e.g. a 3000 x 2000 image is fine. 

 

When you save the image in a jpg format file the image data is compressed to save disk space, so you will see the file size will be considerably smaller, but that's OK.

 

Mark

Edited November 12, 2019 by M.Chapman
Edited to include exact number of bytes required

[MizBrown]

I use 6 MP jpeg as a rough guide for acceptable.  I've had some under that in the 5 MP range get turned down on size.  Six is safer.

Edited October 8, 2018 by MizBrown

[M.Chapman]

11 hours ago, MizBrown said:

I use 6 MP jpeg as a rough guide for acceptable.  I've had some under that in the 5 MP range get turned down on size.  Six is safer.

 

5MP (megapixels) is too small for Alamy. Are you confusing MP (megapixels) with MB (megabytes)?

 

Mark

Edited October 9, 2018 by M.Chapman

[MizBrown]

9 hours ago, M.Chapman said:

 

5MP (megapixels) is too small for Alamy. Are you confusing MP (megapixels) with MB (megabytes)?

 

Mark

 

correct, MB. 

 

[M.Chapman]

3 hours ago, MizBrown said:

 

correct, MB. 

 

 

Using the size of the jpg in MB is not a reliable way of determining if the image size is suitable for Alamy. Images containing lots of detail will produce larger jpgs than those with less detail, even if both images contain the same number of pixels. The level of jpg compression (quality level) also massively affects the jpg size in MB.

 

One easy way to check if images are suitable is to use the Alamy checker app here  http://www.braeside.plus.com/photography/alamy/alamy.html, or simply set Photoshop to permanently show image size information on screen by clicking on the > at bottom left of the screen and selecting Document dimensions (which will display the size in pixels providing Preferences>Rulers and Units are set to Pixels) or Document Sizes (to display the size in MB which appears as two numbers, the first is the 16 bit size, the second is the 8 bit size, which is the one needed for Alamy) .

 

Mark

Edited October 9, 2018 by M.Chapman

[Inchiquin]

On 10/8/2018 at 17:28, Jill Morgan said:

The minimum size confuses many people. The 17MB minimum is related to your RAW file size just before you turn it in to a jpeg.

 

 

 

Sorry Jill, but that's also confusing. It has nothing to do with the RAW file size. It's the uncompressed image size. RAW files are usually compressed and so the file size bears no relation to the image size.

 

Alan

[MDM]

1 hour ago, Inchiquin said:

 

Sorry Jill, but that's also confusing. It has nothing to do with the RAW file size. It's the uncompressed image size. RAW files are usually compressed and so the file size bears no relation to the image size.

 

Alan

 

True. I think Jill knows what she means but has not expressed it very well. Fundamentally the important parameter is the number of pixels in the image which is not directly proportional to the file size on disk  as this can vary widely for compressed file formats depending on the content of the image.  This includes raw files, JPEGs and even TIFFs if compressed. The number of pixels in the raw image is the same as in the converted image unless it has been cropped. For uncompressed file formats there is a direct proportionality between the number of pixels in the image and the file size on disk but that is a diversion here.

 

The problem here really lies in terminology and Alamy's use of the term uncompressed file size does not help.  For Photoshop users the Image Size dialog gives the exact size as required by Alamy if the image is already 8 bit or as Mike has said the little box on the bottom left gives the same. Lightroom shows the same in MB in the metadaa tab iin the Library module if set to show IPTC and can more conveniently show the size in MP in the view options. The conversion from MP to MB is a trivial x3 for 8 bit files.

 

This has been going on for years and nobody at Alamy has ever done anything to properly resolve it by writing some clear and consistent guidance relating to the major image editing programs. 

 

 

Edited October 10, 2018 by MDM

[M.Chapman]

9 hours ago, MDM said:

 

True. I think Jill knows what she means but has not expressed it very well. Fundamentally the important parameter is the number of pixels in the image which is not directly proportional to the file size on disk  as this can vary widely for compressed file formats depending on the content of the image.  This includes raw files, JPEGs and even TIFFs if compressed. The number of pixels in the raw image is the same as in the converted image unless it has been cropped. For uncompressed file formats there is a direct proportionality between the number of pixels in the image and the file size on disk but that is a diversion here.

 

The problem here really lies in terminology and Alamy's use of the term uncompressed file size does not help.  For Photoshop users the Image Size dialog gives the exact size as required by Alamy if the image is already 8 bit or as Mike has said the little box on the bottom left gives the same. Lightroom shows the same in MB in the metadaa tab iin the Library module if set to show IPTC and can more conveniently show the size in MP in the view options. The conversion from MP to MB is a trivial x3 for 8 bit files.

 

This has been going on for years and nobody at Alamy has ever done anything to properly resolve it by writing some clear and consistent guidance relating to the major image editing programs. 

 

 

 

Very well put. If Alamy just stated the minimum number of pixels must be in the image, then the confusion would go away. The fact that they haven't done this (in spite of neverending queries on the forum) suggests that they maybe deliberately using complex terminology as part of the "Alamy QC entrance exam".

 

Mark

Edited October 10, 2018 by M.Chapman

[Fahd Khan]

I never checked the file size ever, and never failed due to file size.

I shoot raw with my Nikon D810 and upload the pictures after editing in LR.

I sometime crop to my taste and some time I leave all 36mp without crop. 

 

Khan

 

[Keith Douglas]

20 hours ago, MDM said:

 

True. I think Jill knows what she means but has not expressed it very well. Fundamentally the important parameter is the number of pixels in the image which is not directly proportional to the file size on disk  as this can vary widely for compressed file formats depending on the content of the image.  This includes raw files, JPEGs and even TIFFs if compressed. The number of pixels in the raw image is the same as in the converted image unless it has been cropped. For uncompressed file formats there is a direct proportionality between the number of pixels in the image and the file size on disk but that is a diversion here.

 

The problem here really lies in terminology and Alamy's use of the term uncompressed file size does not help.  For Photoshop users the Image Size dialog gives the exact size as required by Alamy if the image is already 8 bit or as Mike has said the little box on the bottom left gives the same. Lightroom shows the same in MB in the metadaa tab iin the Library module if set to show IPTC and can more conveniently show the size in MP in the view options. The conversion from MP to MB is a trivial x3 for 8 bit files.

 

This has been going on for years and nobody at Alamy has ever done anything to properly resolve it by writing some clear and consistent guidance relating to the major image editing programs. 

 

 

 

To cause further confusion, I must challenge your statement that "The conversion from MP to MB is a trivial x3 for 8 bit files". In fact one Megabyte is actually 1024 x1024 bits = 1048576 bits. So, to convert from MP to MB you multiply by 3 and then divide by 1.048576.

 

So, an image that is size 3000 x 2000 is 6 million pixels which is 17.166 M bytes (which is where the 17 Mbytes comes from) .

 

There's a simple method of dealing with this which is to multiply the height of the image in pixels by the width of the image in pixels, and if the answer is 6,000,000 or more then the image is large enough. I really don't understand why it needs to be made more complicated than that.

 

Those who fully understand pixels, bits, bytes and are confident that when Alamy say 17 Mbytes they mean slightly less than a 3000 x 2000 image (I'm not), can squeeze out a few more pixels, but I think that the 6 million pixels rule of thumb is much more practical.

[MDM]

8 hours ago, Keith Douglas said:

 

To cause further confusion, I must challenge your statement that "The conversion from MP to MB is a trivial x3 for 8 bit files". In fact one Megabyte is actually 1024 x1024 bits = 1048576 bits. So, to convert from MP to MB you multiply by 3 and then divide by 1.048576.

 

So, an image that is size 3000 x 2000 is 6 million pixels which is 17.166 M bytes (which is where the 17 Mbytes comes from) .

 

There's a simple method of dealing with this which is to multiply the height of the image in pixels by the width of the image in pixels, and if the answer is 6,000,000 or more then the image is large enough. I really don't understand why it needs to be made more complicated than that.

 

Those who fully understand pixels, bits, bytes and are confident that when Alamy say 17 Mbytes they mean slightly less than a 3000 x 2000 image (I'm not), can squeeze out a few more pixels, but I think that the 6 million pixels rule of thumb is much more practical.

Of course you are correct and I was aware of that when posting but I didn’t want to make it any more complicated and for almost all practical purposes it will make no difference. 

[M.Chapman]

13 hours ago, Keith Douglas said:

To cause further confusion, I must challenge your statement that "The conversion from MP to MB is a trivial x3 for 8 bit files". In fact one Megabyte is actually 1024 x1024 bits = 1048576 bits. So, to convert from MP to MB you multiply by 3 and then divide by 1.048576.

 

Or maybe not?  https://en.wikipedia.org/wiki/Megabyte

Fortunately Alamy, PS, LR and the Alamy size checker all use the same 1024 x 1024 definition for Megabyte which you quoted above.

 

Mark

 

[CAROL SAUNDERS]

Hi all, am just wondering with a lot higher megapixel cameras available nowadays when is big too big image wise for here?  i.e., if for example you had a d850 and used at maximum pixels, even when converted to jpeg the file would be pretty huge.  I know size isn't everything so they say just wondering what folk to who use i.e., an 850 or 810 do, apologies in advance if this has been asked before, I think somewhere in this thread Fahd Khan has an 810 and doesn't crop just interested to know what others do. 

 

Thanks

 

Carol

[spacecadet]

IIRC some contributors are downsizing images from the very largest FF sensors because they are a little too unforgiving at 100%.

BTW converting to jpeg per se makes no difference to image size, only file size. I don't think that's what your question was about.

[MDM]

3 hours ago, CAROL SAUNDERS said:

Hi all, am just wondering with a lot higher megapixel cameras available nowadays when is big too big image wise for here?  i.e., if for example you had a d850 and used at maximum pixels, even when converted to jpeg the file would be pretty huge.  I know size isn't everything so they say just wondering what folk to who use i.e., an 850 or 810 do, apologies in advance if this has been asked before, I think somewhere in this thread Fahd Khan has an 810 and doesn't crop just interested to know what others do. 

 

Thanks

 

Carol

 

The file size on disk is not relevant, only the pixel dimensions. Years ago there used to be mention of a 25MB disk size but that is ancient and certainly had not been the case for a long time. Max file size (pixel dimensions) was 200MB. I’ve hit that limit with some panoramas. I am not sure if it still applies. The files got rejected by the system but no QC failure. 

 

I have been using high MP cameras since the D800 and there is no problem at full size as long as the lens is up to the job. The D850 is about 136 MB (approx before Keith takes issue with the calculation 😎) so well below that limit and there would be no reason to downsize if using good lenses but there is an awful lot of crop space in these images which is a massive advantage in certain circumstances. 

[CAROL SAUNDERS]

Thanks everyone, yes the D850 does indeed produce massive files, had a play with one the other day and when converted to jpeg it produced a massive 130MB  !

 

Carol

[Stockybro]

I'm still confuse for 17 MB or file size. Can someone guide me for this

[John Mitchell]

58 minutes ago, Stockybro said:

I'm still confuse for 17 MB or file size. Can someone guide me for this

 

Open up your JPEGs in your editing software (e.g. Photoshop). If they are17 MB or larger, then you can submit them to Alamy.

 

If your camera is at least six megapixels, then there shouldn't be a problem as long as you haven't done any cropping.

Edited March 27, 2021 by John Mitchell