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Guides
The tools do the work. These pages explain what is going on underneath, which is usually what you need when a tool has not solved your problem and you cannot see why.
- Photo and signature sizes for exam forms Reading the specification properly, and what to do when it contradicts itself
- How JPEG quality maps to file size Why the quality number is not a percentage of anything
- Why your PDF is so large Four causes, in the order worth checking
A note on the advice here
Upload validators are not documented, are not consistent between systems, and change without announcement. Anything written here about how a particular kind of form behaves comes from observation rather than from a specification, so treat it as a good starting assumption rather than a guarantee. Where something is genuinely uncertain, these pages say so.