Images go in one per page, in the order your file picker hands them over — there is no way to reorder them here, so name them in the order you want first. A JPG is placed in the PDF as it is. A PNG keeps every pixel but is stored again in the PDF’s own lossless format. Anything else, WEBP included, is redrawn as JPEG.
The PDF engine (about 500 KB) loads only when you drop a file in, so the page itself stays light. Your file is read on your own machine and never sent anywhere. Open your browser’s network tab and watch while you use it.
A JPG is not: the same compressed data is placed in the page. A PNG is decoded and stored again losslessly, so no quality is lost, but the PDF can come out larger than the file you started with. Any other format is redrawn and saved as JPEG at 92 percent, and the line under the button says how many files that happened to.
With "Fit each image" the page is made as many points as the image has pixels, and there are 72 points to an inch, so a 4000 pixel wide photo becomes a page about 140 cm across. Choose A4 if it is going to be printed.
Fifty. Files past the fiftieth are left out of the selection without a warning. Choosing files a second time replaces the first set rather than adding to it, so pick them all in one go.
A JPG is embedded exactly as it is, and nothing here reads the orientation tag that phone cameras write, so a photo your gallery shows upright can land on its side. Re-save it the right way up in a photo editor first.
These all work the same way, in your browser. Most are free; the ones marked as needing a plan are not.
A new DeskKit tool lands every week or two. Leave an address to hear about it. Nothing else is ever sent, and one click removes you.