You upload your photograph. The portal says "Photo and signature invalid" and clears the field. It does not say whether the problem is the size, the dimensions, the format or something it can see and you cannot. So you resize it slightly, try again, get the same message, and lose an afternoon to a form that should have taken fifteen minutes.

The frustrating part is that the portal knows exactly what is wrong. It just does not tell you. Here is the full list of what these forms check, roughly in the order they usually fail.

1. File size, at both ends

Everyone expects the upper limit. Fewer people know that many Indian exam portals enforce a minimum too - "20 KB to 50 KB" means a 12 KB file is refused as well as a 60 KB one. A clean, high-contrast scan of a signature compresses down to almost nothing, so this catches people whose file looks perfect. If you have been shrinking your file further and further and it keeps failing, you may have overshot the floor.

2. Pixel dimensions

IBPS wants a photo at exactly 200 x 230 pixels. UPSC wants 350 x 350. If a form states pixel dimensions rather than a ratio, being close is not close enough. Cropping in your phone's gallery app will not give you an exact pixel count.

3. Aspect ratio

Forms that do not state exact pixels usually state a shape instead: 3:4 for photographs, 4:1 for signatures, 4:5 for India Post GDS. A signature photographed on a full sheet of paper is roughly 3:4, nowhere near 4:1, and gets refused on shape before its size is even considered. Trimming the empty paper away is what fixes this.

4. File format

Almost every portal wants JPEG. Some reject PNG outright, and a surprising number reject a file that is named .jpg but is actually a PNG or a WebP inside - which happens routinely when you save an image from WhatsApp or a browser and rename it. Renaming a file does not change its format.

5. DPI

Some instruction pages specify 200 or 300 DPI. In practice most portals only ever check pixels and file size, and most phone cameras and editors do not write a DPI value into the file at all - so "not recorded" is normal and usually harmless. If yours genuinely enforces it, the value has to be stamped into the file.

6. The photo is too old

RRB and several others require a photograph taken within the last three months. No software can see the age of a photo, and no checker can warn you. It gets caught at document verification instead, which is a much worse place to find out.

7. Missing name and date on the photograph

UPSC requires your name and the date the photo was taken to be printed on the photograph itself. If that strip is missing, the file can pass every numeric check and still be rejected by a human later.

8. The background, and the ink

A plain light background is required almost everywhere. A patterned wall, a doorframe behind your shoulder, or a photographed signature sitting on grey-looking paper all count against you. Signatures are normally required in black or blue ink - pencil, green ink and light gel pens get refused.

Finding out which one it is, in seconds

Rather than guessing, drop the file into the Form Upload Checker and pick the exam you are applying to. It reads the file in your browser and gives you a table: each requirement, what the form wants, what your file actually is, and a pass or fail against each one. So instead of "invalid", you get "size 68 KB, needs 20-50 KB" and you know precisely what to change.

Where the problem is fixable from the file itself, the "Fix it for me" button hands the file straight to the Exam Photo and Signature Resizer with the right spec already selected, and you download a corrected copy.

If it still gets rejected after all the numbers are right

Then it is one of the four things nothing can read from a file: the photo's age, a missing name-and-date strip, a background that is not plain enough, or the wrong ink colour in the signature. Those four are the usual culprits once the numbers check out. Re-read the instruction page specifically for them before you assume the portal is broken.

A fifth possibility, worth checking early because it wastes so much time: the portal itself. Several Indian application sites behave badly in some browsers, silently fail if the upload times out, or reject files whose names contain spaces, brackets or non-English characters. Rename your file to something plain like photo.jpg, try a different browser, and try outside the last-day rush when these servers are at their worst.

Getting it right the first time next year

• Get a proper passport photograph taken against a plain white background, and ask the studio for the digital file, not just prints. One good original serves every form you will ever fill.
• Sign on plain white paper in black or blue ink and photograph it straight-on in even light. If the result looks grey or shadowed, the Signature Cleanup tool lifts the ink onto a genuinely clean background.
• Keep the originals in a folder and resize a copy per exam. Never resize your only copy - each round of compression loses quality permanently, and you cannot go back up.
• Read the instruction page even when you have applied to the same exam before. These specs change between cycles.

The checker is free, runs entirely in your browser, and does not even record that you used it - the file you are troubleshooting never leaves your device.