Quick answer
One of the most common image upload problems is a portal that accepts only small photo files. Many visa, passport, exam, and job application websites ask for a JPG under 100KB, and they often reject files with a vague error message like file too large or invalid image size.
The easiest way to handle that requirement is to start with a tool that lets you aim for the actual limit. Generic compressors can make the file smaller, but they do not always get you close to the number the website asks for. If the portal says 100KB, it usually saves time to start there and adjust only as much as needed.
What usually works best
This matters most for official submissions. Over-compressing a photo can make it blurry, while under-compressing means you keep hitting the same upload error again and again. ExactSizer is built for that last-mile step where you need a file that lands near a strict limit without unnecessary guesswork.
For passport photos, visa forms, and administration sites, JPG is usually the safest format. If your image starts as PNG or another export, it often helps to use the JPG path because it reaches small file sizes more efficiently. That gives you a better chance of staying within the limit while keeping the face and document details readable.
If it still fails
If you still see upload problems after reducing the file size, the issue may be dimensions rather than weight. Some portals expect both a maximum file size and a reasonable pixel size. In that case, resizing the image before compressing it is often the fastest fix.
The practical pattern is simple: upload the photo, aim for 100KB, and if the site still complains, use the advanced resize controls to reduce width or height slightly. That is faster than trying multiple random compressors and reuploading each attempt.