Convert PNG to PDF
Most converters quietly re-compress your screenshots as JPEG on the way in. This one tells you, and will not do it if you say not to.
Lossless keeps screenshots, charts and line art crisp and produces a much larger PDF. JPEG is the right choice for photographs.
“Fit the image” makes each page exactly the shape of its picture, with no margins — sized as if the image were 96 dpi.
Where PNG-to-PDF converters usually lose something
A PDF can embed JPEG data directly — the format has a filter, DCTDecode, that means “this stream is a JPEG, hand it to the JPEG decoder”. That makes JPEG the path of least resistance for anyone writing a converter: decode the PNG, re-encode as JPEG, drop the bytes in, done. The result is small and, for a photograph, perfectly good.
For the things people actually keep as PNGs it is not good. Screenshots, chart exports, scanned forms, receipts, logos and line art are full of hard edges and flat colour, which is exactly what JPEG handles worst: coloured fringing around every letter, mottling across areas that should be one flat tone. You saved a PNG precisely to avoid that, and the converter undid it without mentioning it. So this page offers both, and defaults to the one that does not.
How the lossless mode works
In lossless mode the pixels go into the PDF as a Flate stream — the same compression family PNG itself uses — with no re-encoding step in between. Two details make it practical:
- Palette storage. If the image uses 256 colours or fewer, which covers most screenshots, diagrams and exported charts, the page is written with an indexed colour space: one byte per pixel instead of three. That is a straight two-thirds saving with nothing lost.
- Real transparency. Alpha is carried as a soft mask, so a PNG with a transparent background sits on the page background rather than on an unexpected black or white rectangle.
The trade is size. A lossless page from a large screenshot can run to a few megabytes; the same image through the JPEG mode is usually under 200 KB. If you are emailing a fifty-page batch, the JPEG mode is the sane choice. If you are filing a document that someone will zoom into, it is not.
Page size, order and orientation
A4 and US Letter both centre the image on the page with a small margin, and pick portrait or landscape per page based on the image's own proportions. “Fit the image” skips the paper metaphor entirely: each page becomes exactly the shape of its picture, no margins, sized as though the image were 96 dpi — the resolution Windows and virtually every screenshot tool assume. That is the right mode for something that will be read on screen and the wrong one for something that will be printed.
Pages appear in the order you picked the files. The list under the drop zone shows that order and each row has a control to move it up, so you can fix it without re-selecting everything. Images are capped at 1400 px on the long side in lossless mode and 1600 px in JPEG mode; beyond that the file grows much faster than the visible detail.
What this does not do
There is no OCR. The PDF contains pictures, so text inside your screenshots is not selectable, not searchable and not accessible to a screen reader. Nothing here adds a password, signs anything, or shrinks an existing PDF. If your inputs are photographs rather than screenshots, JPG to PDF is the same builder tuned for that case.
Common questions
Which mode should I pick?
Lossless for screenshots, charts, scans, forms, logos and anything with text or hard edges. JPEG for photographs, or when the PDF has to be small enough to email. The default is lossless because that is usually why the source was a PNG.
Why is the lossless PDF so large?
Because it stores the pixels rather than an approximation of them. Expect a few megabytes per full-size page. Images with 256 colours or fewer are stored as a palette, which cuts that by roughly two thirds automatically.
Can I change the page order?
Yes. Pages follow the order you selected the files in, and each row in the list has a control that moves it up one place.
Will the text in my screenshot be searchable?
No. This builds a PDF of images. There is no OCR step, so the text is pixels, not characters. Any converter that promises otherwise is running OCR, usually on a server.
Does a transparent PNG stay transparent?
In lossless mode, yes — the alpha channel becomes a soft mask in the PDF. In JPEG mode it cannot, so transparent areas are filled with white.
Are my files uploaded anywhere?
No. The PDF is assembled byte by byte in your browser by this page's own code. There is no server component to send anything to.