The image resolution for a PDF and for a web site are necessarily different but Confluence uses the same image for both.

Right now I've got one resolution for the web but I'd like a much higher resolution image for the PDF.

One solution could be adding a size tag to images on the wiki input, e.g.

and then attaching a high res picture with confluence downsampling for display

A second solution coulde be to attach two images to a page and have confluence know how to do the right thing.

A third solution would be to have confluence support svg.

cheers,
adrian