Each page comes out as its own image, named after the file with the page number on the end. The setting labelled Quality is the resolution, 72 to 288 DPI: 288 is four times the width of 72, so sixteen times as many pixels. Every page is drawn onto white first, so a PNG from here has no transparency.
The PDF reader 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 PDF page is measured in points, 72 to the inch, so 72 DPI gives one pixel per point and 288 DPI gives four. An A4 page at 288 DPI comes out around 2380 by 3370 pixels.
No. A PDF page has no background of its own, and left transparent it would come out black in a JPG, so white is laid down before the page is drawn. PNG is given the same white ground. Pick it for sharpness, not for transparency.
No. The setting called Quality is the resolution; the JPEG quality itself is fixed at 92 percent. That is high enough that the compression is hard to see, but if you want the pixels exactly as they were drawn, take PNG instead.
It saves the images one at a time, about a quarter of a second apart, rather than bundling them into a zip. Forty pages means forty files arriving in your downloads folder, and your browser may ask whether to allow that, or block the later ones.
These all work the same way, in your browser. Most are free; the ones marked as needing a plan are not.
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