JPG or PNG when turning PDF pages into images?
The choice takes five seconds if you know one thing: JPG was designed for photographs and PNG for drawings. Pick the wrong one and your text looks like it has been rained on.
The short answer
Is the page mostly photographs? JPG. It compresses gradients beautifully and the file is a fraction of the size.
Is the page text, a table, a diagram or a screenshot? PNG. It loses nothing, so letters keep their clean edges and thin lines stay thin.
JPG works by throwing away detail your eye barely notices in a photograph. On a sharp edge — the outline of a letter — that same trick leaves a grey halo. That halo is the blurry text everyone complains about.
What DPI you need
DPI decides how many pixels each page becomes. An A4 page at 150 DPI is about 1240×1754 pixels; at 300 DPI it is 2480×3508, which is four times the pixels and roughly four times the weight.
96 DPI is enough for a thumbnail or a preview on screen. 150 DPI is the sensible default: it reads well on any screen and stays a reasonable size. 300 DPI is for printing or for reading small print with a zoom; above that you are making a heavier file with no visible gain.
Keep the pages straight
A page that the document asks to rotate must come out already rotated, and the image must have exactly the proportions of the page — not stretched to a square, not cropped at the margins. It sounds obvious and it is the most common defect in converted images.
If a document mixes sizes — an A4 report with one landscape page in the middle — each image should keep its own size. Forcing them all to one shape is what ruins charts.
PDF to JPG or PNG in CLEKARA keeps each page's size and orientation and offers both formats; several pages come down together in a ZIP.
Two things worth knowing
An image is not searchable. Once a page becomes a picture, nobody can select a word in it or search inside it. If you need the text, convert to Word or Excel instead — an image is for showing, not for working.
PNG supports transparency; JPG does not. If you are going to place the page over a coloured background, PNG is the only one that will not bring a white rectangle with it.