Find out which limit you have exceeded
A website may restrict each file, the combined attachments, or the whole submission. It may also set different allowances for different document categories. Read the wording beside the failed field and any linked help. A number from another page or another organisation is not a reliable substitute for the rule you need.
Separate storage size from other meanings of large. A photograph can have too many pixels while occupying comparatively few bytes. A PDF can have more pages than allowed even when its file size is modest. If the error mentions width, height or pages, reducing the MB figure alone may leave the relevant problem unchanged.
Write down both the value and the unit. A maximum of 500 KB is not the same as 5 MB. Check whether a lower limit is also stated: some forms require a file to sit within a range. Make My Files Work's compatibility fields currently check a maximum byte size, so a minimum file-size condition needs a separate manual comparison.
Compare the exact copy you plan to submit
Use your device's file information or a local file size check on the selected copy. Several files can share a similar name while containing different exports. A photo in the camera folder, a version sent through a messaging app and a downloaded conversion may have very different dimensions and sizes.
Round numbers can conceal a small excess. A displayed 2.00 MB is not necessarily exactly 2,000,000 bytes. Decimal MB and binary MiB use different calculations, and some interfaces call both MB. Make My Files Work's current maximum-MB field calculates 1 MB as 1,048,576 bytes. Treat an exact limit from the recipient as the authority.
If the website says under a limit, leave practical headroom when possible. Do not reduce the file all the way to the smallest size you can achieve; readable text and suitable image detail matter. The goal is an acceptable submission, not a record-breaking compression percentage.
For photos, start with unnecessary dimensions
A large camera photograph may contain far more pixels than an ordinary upload requires. If the destination specifies smaller dimensions, an appropriately resized export may reduce storage substantially. Preserve the intended shape and check the required minimum before making the image smaller. A tiny preview is not enough to judge whether the result remains useful.
Choose a format suited to the content and accepted by the destination. JPEG is commonly suitable for photographs; PNG can be useful for sharp graphics or transparency. Converting a photograph to PNG does not guarantee a smaller result. Equally, converting a transparent graphic to JPEG requires a background and may make fine edges less clean.
Use a target-size tool only after you understand the constraints. Make My Files Work's under-size tools make a checked attempt and can refuse an unreachable target. Their preset labels use binary KiB or MiB thresholds. They do not promise that every image can become tiny while retaining all its detail.
For PDFs, work out what makes the document heavy
Scanned pages are often stored as pictures, whereas an exported text document may contain compact text and drawing instructions. Those files respond differently to compression. The number of pages alone does not tell you how much reduction is possible: a single detailed colour scan can be larger than a much longer text document.
Make My Files Work repacks readable PDFs without intentionally rasterising their text. It does not offer adjustable image downsampling inside scanned PDFs. If that method cannot reach your target, repeatedly running it will not discover a hidden aggressive setting. Return to the source document or scanner and consider a more suitable export, while retaining legibility.
Do not delete evidence, required blank forms or signed pages just to reduce bytes. Splitting a PDF is appropriate only where separate documents are permitted. Read the resulting files in order and make sure the recipient can understand what each part contains. Keep the complete original for your records.
For other formats, use the application that created them
Office documents, videos, presentations and archives can need specialist export settings. Make My Files Work's processing tools focus on supported images and PDFs. A file's size can be measured even when the site cannot convert its contents, but a supported measurement is not evidence that every transformation is available.
If the recipient permits PDF, exporting a document from its original application may help preserve the intended layout. If it requires an editable file, a PDF is not an interchangeable replacement. Ask for clarification where the required format is ambiguous instead of choosing whichever export happens to be smallest.
ZIP is only useful when the receiving service accepts it. Already compressed media may shrink very little, and an archive adds an extra step for the recipient. Do not hide an unsupported file inside a ZIP and assume the portal's rules no longer apply.
Review the output before the next attempt
Check the new size first, then inspect the contents. For documents, read small print, dates, stamps and signatures. For images, look at faces, edges and any writing. Confirm that the full page or subject remains visible and that orientation has not changed unexpectedly. A successful download does not replace this review.
Give the finished copy a distinguishable name and choose it deliberately in the form. Remove an earlier attachment if the page still lists it. If several files are allowed, verify the total as well as each item. Record a submission receipt when the website offers one.
When a smaller file still fails
Read the current error rather than assuming it remains a size issue. The portal may now be rejecting the format, an encrypted PDF, an expired session or an unrelated account restriction. Once the file is comfortably within the published size rule, further compression may only damage useful detail.
Contact the receiving organisation when the rules and measured file appear to agree. Provide the exact message, the field name and the file's size and format. Ask about the correct route for a document that cannot be made smaller while remaining complete and readable. Keep sensitive attachments out of an ordinary support message unless an approved channel is provided.
Questions that come up
Can I reduce a file by renaming it?
Changing the name leaves the contents and stored byte count unchanged. A genuine compression or smaller export is needed when the file exceeds a byte limit. Renaming can only address a separate filename problem.
Does a smaller file mean lower quality?
Not always. Removing unnecessary storage overhead can reduce bytes without changing visible detail. Reducing image resolution or using lossy compression can affect quality, so the amount and method of reduction both matter.