They're not interchangeable. The right choice depends on whether you're sending a document or a picture — and what the other person will do with it.
The quick rule
Send a PDF for anything that's a document — multi-page files, forms, contracts, invoices, CVs, anything that should print cleanly and look the same on every device. Send a JPG for a single photo or image — a picture, a screenshot, something going into a social post or a chat.
When PDF wins
Multiple pages in one tidy file — JPGs can't hold several pages.
Consistent layout — a PDF looks identical everywhere; fonts and spacing don't shift.
Selectable text — readers can search, copy, or run OCR.
Printing — PDFs are built for accurate, page-sized output.
Forms — fillable fields and signatures live in PDFs, not images.
When JPG wins
A single photo where layout doesn't matter.
Social media and chats that preview images but not PDFs.
Quick previews — a JPG shows instantly without a PDF viewer.
Editing in an image app that doesn't open PDFs.
Convert either way, privately
Whichever you need, meldpdf converts in your browser without uploading:
Photos or scans to send as a document → JPG to PDF.
A PDF page you want to post as an image → PDF to JPG.
Frequently asked questions
Is a PDF or JPG smaller?
It depends on content. A text document is tiny as a PDF; a detailed photo is often smaller as a JPG. For shrinking a heavy PDF, see reduce PDF size.
Can I put several JPGs into one file?
Yes — combine them into a single PDF with JPG to PDF.
Does converting upload my file?
No. Conversion runs locally in your browser. See our privacy policy.