Photo file size too big: meeting kilobyte limits

Kilobytes are the file limit people discover last, usually when a portal refuses an upload that has the right pixels. File size depends on JPEG compression, not on dimensions, so a 600 x 600 photo can weigh 80 KB or 400 KB depending on how it was saved. This guide lists the limits that bite, shows how to get under one without wrecking the image, and explains the minimum-size limits that catch over-compressed files from the other direction.

The limits that actually bite

The strictest limits are far smaller than a phone photo. China's online passport renewal takes 20 to 80 KB for the renewal upload; the US CEAC visa system caps the DS-160 photo at 240 KB and, in some browsers, rejects larger files silently by just reloading the page. Korea's online re-issue allows 500 KB for the Korean passport, and Japan's マイナポータル takes 600 KB for the Japanese passport and compresses anything larger itself, which can soften the image below what the examiner accepts. The generous end is the UK's 10 MB ceiling for the digital passport photo.

Shrink kilobytes with quality, not pixels

There are two levers: fewer pixels or stronger compression. Use pixels first only down to the document's target size, never below its minimum, then let JPEG quality do the rest. Re-encoding at a lower quality is invisible long before it is destructive; resizing below the minimum is an instant refusal. The order matters because every save of a JPEG recompresses it, so make one edit chain from the original camera file rather than repeatedly saving the same file.

This is what our export does mechanically: each portal file is rendered at the document's target pixels and then encoded at the highest JPEG quality that fits under the limit, found by a binary search over quality rather than a single guess. The checklist shows the resulting pixels and kilobytes before you pay, so the number you upload is a number you have seen.

Minimums exist too

Several authorities set a floor as well as a ceiling, to keep out over-compressed files: gov.uk wants at least 50 KB, and the US online renewal wants at least 54 KB for the MyTravelGov upload, alongside its rule that an image sent by text message can fail the compression check. A file under the floor cannot be fixed by re-saving it at higher quality, because the detail is already gone; go back to the original. We never pad a file to reach a minimum; if a source photo is too compressed to clear a floor honestly, the file is flagged in the downloads list instead.

Getting under a limit by hand

If you are preparing a file without our tool, this order avoids the common traps.

1.Find the document's pixel target and KB range on its requirements page; the pixel dimensions guide explains the three ways portals state them.
2.Start from the original camera JPEG, not a screenshot, a WhatsApp download or a previously re-saved copy.
3.Resize to the target pixels in one step.
4.Export at decreasing JPEG quality until the file fits; stop at the first quality that does.
5.Check the result still meets any minimum KB and the aspect ratio before uploading.

Frequently asked questions

Why did my 2 MB upload come back as a 240 KB file elsewhere?

Messaging apps and some portals re-compress images on the way through. That is why rules like the US renewal's say not to send the photo by text message: the recompressed copy may fail the compression check even though the original was fine.