Images to PDF
One image per page — and a plan you can read before you build it: how big each page will be, whether anything is being enlarged, how much a cover fit would crop, and what resolution the result actually prints at.
🔒 Your images stay on this machine — the file never leaves your browser.
Drop JPEG or PNG files here
Several at a time · nothing is uploaded
Three decisions other converters make for you
Enlarging. An image smaller than the page can be stretched to fill it. That adds pixels and no detail — the page looks fine as a thumbnail and soft at full size. Here it is off by default and asking for it is a checkbox, not a silent default.
Cropping. “Cover” fills the page and cuts whatever does not fit. That is usually right for a photo page and always wrong for a scanned document, so how much is being cut is shown per image rather than discovered afterwards.
Resolution. The same image is sharp on a small page and soft on a large one. With a fixed paper size the effective DPI is computed and flagged when it drops below print quality — a number you cannot see by looking at the screen preview.
JPEG and PNG only, deliberately
A PDF carries those two directly. HEIC, WebP, AVIF and TIFF have to be converted first, and doing that quietly would change the file you handed over without telling you. Those are refused by name — the image converter handles the conversion.
Every check this tool runs (5 rules)
IMP-001 The image would be enlarged to fill the page
Scaling an image up adds pixels without adding detail: the page looks right at thumbnail size and soft at full size. By default an image smaller than the page is placed at its own size rather than stretched, and asking for the stretch is a deliberate choice rather than the default.
Fix: Leave upscaling off, or supply an image with more pixels.
yaktool engineering rule, not a citation: the layout decisions when turning images into pages — upscaling, cropping and effective print resolution — are ours, and are stated rather than applied silently.
IMP-002 That image format cannot be embedded in a PDF
PDF carries JPEG and PNG directly. Anything else — HEIC, WebP, AVIF, TIFF — has to be converted to one of those first, and doing that silently would change the file the user handed over without saying so.
Fix: Convert it to JPEG or PNG first, then build the PDF.
yaktool engineering rule, not a citation: the layout decisions when turning images into pages — upscaling, cropping and effective print resolution — are ours, and are stated rather than applied silently.
IMP-003 Cover fitting crops part of the image
Cover fills the page and cuts whatever does not fit, which is usually what you want for a photo page and never what you want for a scanned document. How much is being cut is reported so the choice is visible.
yaktool engineering rule, not a citation: the layout decisions when turning images into pages — upscaling, cropping and effective print resolution — are ours, and are stated rather than applied silently.
IMP-005 The image’s dimensions could not be read
Width and height came back as zero, which means the file could not be decoded — a truncated download, a mislabelled extension, or an image the browser will not open. Building a page from it would produce a zero-sized page that looks like a bug in the PDF rather than a problem with the input, so it is refused with its name instead.
Fix: Open the file to confirm it is a valid image, then try again.
yaktool engineering rule, not a citation: the layout decisions when turning images into pages — upscaling, cropping and effective print resolution — are ours, and are stated rather than applied silently.
IMP-004 The image is below print resolution at this page size
Effective resolution is pixels divided by printed size, so the same image is sharp on a small page and soft on a large one. Below roughly 150 DPI the difference is visible in print even when the screen preview looks fine.
Fix: Use a smaller page, or an image with more pixels.
yaktool engineering rule, not a citation: the layout decisions when turning images into pages — upscaling, cropping and effective print resolution — are ours, and are stated rather than applied silently.