Image Sizing Targets


Today’s Question: I want to enter a photo contest that asks for 5MB image saved as a JPEG, at 300 ppi resolution. Isn’t this a strange setting? I have the photo as a 5MB TIFF now, but can’t seem to get it over to the JPEG without losing the 5MB!

Tim’s Quick Answer: The settings you’ve provided are indeed strange, and in large part completely useless for this purpose. I would suggest first saving the image at the original pixel dimensions as a JPEG image at a Quality setting of 80 if you are using Lightroom or 8 if you are using Photoshop. Unless you’re working with a photo with extreme resolution, this will produce a file of under 5MB that you can submit for the contest.

More Detail: It amazes me how often I see submission guidelines for images that don’t provide an adequate amount of information, and that make it clear that the person writing the guidelines doesn’t know much about resolution. In many cases the primary motivation seems to be to ensure that the submitted image files aren’t too large, in an effort to prevent an overload of the server (or an excessive cost for online storage).

The 5MB size is most certainly an upper limit intended to prevent huge image files from being submitted. But with a JPEG file there is always compression applied, so the chances of ending up with a file over 5MB are pretty slim. Even at the maximum Quality setting for a JPEG image, you would need to have pixel dimensions of around 5,000 or so pixels on the long side to produce an image file of around 5MB. Plus, there’s no real advantage to that file size in this context.

Instead I would submit images at either full resolution or a bit smaller if you’re concerned about producing a file that is too large. For a photo contest I generally want to have an image that is large enough to be evaluated effectively, enabling the judge to zoom in on the image, for example.

Frankly, I would ignore the pixel per inch resolution altogether in this case. This setting only applies when the photo is being printed, so it isn’t critical for an online photo contest submission.

Of course, it perhaps goes without saying that it is a good idea to confirm that the photo contest is being run by a reputable organization, and to check the submission guidelines carefully. If you have any doubts about these issues it may not be worthwhile to submit your photos for the contest, especially if you are sending relatively high-resolution image files.