Why File Size Limits Exist (and How to Work Around Them)
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Email providers, web forms, and file upload systems almost always enforce a maximum file size — commonly 10–25MB for email attachments, sometimes much smaller for web forms. These limits exist mainly to protect server storage and bandwidth costs, and to keep large attachments from clogging inboxes and slowing down mail delivery for everyone.
When a file is too large, there are really two different strategies, and picking the right one depends on why the file is large. If the size comes from high-resolution images inside a PDF, compressing the PDF directly is the fastest fix and preserves the document as a single file. If the file is large simply because it has an enormous number of pages, compression alone may not get it under the limit, and splitting it into smaller multi-part files is often the more reliable solution.
It's worth checking which limit you're actually up against before choosing a strategy: some services limit the size of a single file, while others limit total attachment size across multiple files in one message, which changes whether splitting a large file into parts actually helps.