Resizing image for competition entry

[DJ72]

Hi Gurus.

 

So I am going to enter the Lens Culture Portrait Awards 2020. The rules state:

 

Quote

For best results, upload the highest-quality JPEGs, sized a minimum of 1200 pixels on the longest side but up to 2000 pixels is even better. Maximum size is 10MB.

 

In Lightroom, I select Long Edge and choose 200 pixels. When I export this the image is reduced to just over 2MB.

 

I started out just exporting it to be under 10MB, but with the "longest side" rule, the image size is now much smaller.

 

Should I be worried? My concern is that this reduces the image resolution and quality. Does it? Or is there a better way to do this?Insert image from URL

 

Thank you,

DJ 

[Harry Harrison]

32 minutes ago, DJ72 said:

In Lightroom, I select Long Edge and choose 200 pixels.

You meant to say 2000 pixels didn't you? 2000 pixels on the long side is quite small in terms of pixel dimensions (2.7 MP) so a 2MB jpeg is par for the course, though that is governed by the actual detail in the image. Provided you've saved it at the highest quality it will be fine.

[DJ72]

Yes thanks Harry I did mean 2000. So my thinking is sound then.

 

It just seems a shame to reduce what was a 40M image to a piddly 2M. But then perhaps they will ask for an original once I am chosen as the winner (which is a cert, obviously 😉).

 

And comparing them on my screen they look the same anyway. 

[Harry Harrison]

14 minutes ago, DJ72 said:

they will ask for an original once I am chosen as the winner (which is a cert, obviously 😉).

It's only a matter of time! Yes, they just need a screen image for whoever their adjudicators are. I've always wondered who does the initial checking in these competitions, there are usually some headline judges but I doubt they get to see everything, too busy I imagine.

 

Good luck! 

[spacecadet]

36 minutes ago, DJ72 said:

Yes thanks Harry I did mean 2000. So my thinking is sound then.

 

It just seems a shame to reduce what was a 40M image to a piddly 2M. But then perhaps they will ask for an original once I am chosen as the winner (which is a cert, obviously 😉).

 

And comparing them on my screen they look the same anyway. 

You're not really being asked to do that, I don't think, although they are confusing things by referring to image size and (compressed) file size as if they're the same. My 20MP jpeg exports at 90% quality are in the region of 7-10MB (my emphasis) It's easy to conflate the two.

If exporting from Lightroom, just tick "limit file size" and set 10000K in the export dialogue.  LR will set the quality.

In case you're concerned about that I've tried an export at my usual 90 and another at 50 which halves the file size. The difference in quality is very small at 100%.

Edited February 11, 2020 by spacecadet

[Harry Harrison]

24 minutes ago, spacecadet said:

You're not really being asked to do that

I think that is what they are asking the OP to do in fact, size according to pixel dimensions, a maximum of 2000 pixels on the long side.

 

"upload the highest-quality JPEGs, sized a minimum of 1200 pixels on the longest side but up to 2000 pixels is even better"

 

 

[spacecadet]

7 minutes ago, Harry Harrison said:

I think that is what they are asking the OP to do in fact, size according to pixel dimensions, a maximum of 2000 pixels on the long side.

 

"upload the highest-quality JPEGs, sized a minimum of 1200 pixels on the longest side but up to 2000 pixels is even better"

 

 

I meant being asked to reduce a 40MP image to 2 MP. The stated maximum compressed file size is 10MB- as I said my 20MP exports are rarely larger than 10MB.

[MDM]

28 minutes ago, Harry Harrison said:

I think that is what they are asking the OP to do in fact, size according to pixel dimensions, a maximum of 2000 pixels on the long side.

 

"upload the highest-quality JPEGs, sized a minimum of 1200 pixels on the longest side but up to 2000 pixels is even better"

 

 

 

Harry is correct and it is quite clear that is what they are asking for by logical deduction. Max of 2000 pixels on the longest side is clear in itself.  The 10MB max has to be the pixel dimensions as there is no way that a JPEG with max long dimension 2000 pixels could be anywhere near 10MB file size on disk(compressed file size) unless perhaps if it was composed of extremely intricate patterns. The pixel dimensions of a 2000x2000 image is 11.4MB so if it was a square image than it would be necessary to have a smaller max dimension. 

 

EDIT: 1870x1870 is the largest possible image if it was a square crop and comes in at exactly 10MB

Edited February 11, 2020 by MDM

[spacecadet]

IMO that's not the only way to interpret the instructions.

My A58 is quoted at 20MP and the sensor is 5456x3632px.. 5456x3632=19816192. I am aware that three bytes are required to represent each pixel. I was under the impression, and have been for many years, that MB signified file size, not image size, vide the many confused posts from new contributors, but if I am wrong, I stand corrected and will no longer contribute to threads such as this.

Edited February 11, 2020 by spacecadet

[Harry Harrison]

11 minutes ago, spacecadet said:

I was under the impression, and have been for many years, that MB signified file size, not image size

There's a difference here, unlike Alamy the competition is simply quoting a maximum and minimum pixel dimension for the longest side. It was the OP that brought in MB and so unnecessarily complicated the situation  for himself. 

 

Some of us might wish that Alamy simplified things for new contributors in a broadly similar fashion, to ask for a minimum image size of 6 Megapixels, 6,000,000 pixels, so height x width in pixels is more than 6,000,000 pixels, but that is a separate issue.

[MDM]

 

Quote

IMO that's not the only way to interpret the instructions.

My A58 is quoted at 20MP and the sensor is 5456x3632px.. 5456x3632=19816192. I am aware that three bytes are required to represent each pixel. I was under the impression, and have been for many years, that MB signified file size, not image size, vide the many confused posts from new contributors, but if I am wrong, I stand corrected and will no longer contribute to threads such as this.

 

 

I think you are becoming oversensitive. What I said was not a personal slight against you, it was simply the only rational conclusion. I was trying to present a rational argument to clarify. It is not my intention to fall out with you. I say things as I see them (as yesterday in the slide copy thread).

 

They actually state the pixel size: "For best results, upload the highest-quality JPEGs, sized a minimum of 1200 pixels on the longest side but up to 2000 pixels is even better. "

 

In Photoshop  the image size (pixel dimensions) has always been given in MB in the image size dialog as well as elsewhere. 

Edited February 11, 2020 by MDM

[MDM]

6 minutes ago, Harry Harrison said:

There's a difference here, unlike Alamy the competition is simply quoting a maximum and minimum pixel dimension for the longest side. It was the OP that brought in MB and so unnecessarily complicated the situation  for himself. 

 

Some of us might wish that Alamy simplified things for new contributors in a broadly similar fashion, to ask for a minimum image size of 6 Megapixels, 6,000,000 pixels, so height x width in pixels is more than 6,000,000 pixels, but that is a separate issue.

 

Indeed and it was the OP who got confused. The file size on disk is generally irrelevant unless one is emailing or making images available for download and wants to have small files. 2000 pixels max dimension is common for online competitions.