Adding a list of figures, with captions and thumbnails, in the sidebar is extremely useful, but when you click on the figures to display them as an overlay over the article, they are often far too small, and, although they can be expanded (on a Mac with trackpad gestures), the resolution is too poor to read the text. As an example, in one article (DOI: 10.7566/JPSJ.87.024702), the figures are available in the online HTML version of the article at much higher resolution. If those are inaccessible because they are behind a firewall, then I presume the figures must be generated automatically from the article PDF. If so, please extract them with much higher resolution. They are clear in the article PDF.
Unfortunately us saying that users are having a problem is less effective. If we had it our way all the publishers would deliver the PDF's and metadata the same way! I have raised an issue with the Journal of the paper you mentioned but as with most of these things I will only receive the canned response that they have received a ticket.
It sounds like we would have to leave it to you to negotiate with each publisher. You can obviously say that you have had complaints from your users. Do you know which journals are delinquent here or do you want me to post problem journals as I find them?
This varies greatly on the publisher. Nature for instance sends us the PDF, images, and an xml outlining what the PDF contains while other publishers they give us an xml with hyperlinks to the images. It also changes depending on our contracts with publishers. I can't give you a concrete answer as it changes quite often.
Thanks for the information. I am prepared to contact the publishers when I notice the issue, but could you explain how they "give" you the images. Does the article page contain metadata linking to these images?
It appears the publisher has given us these low res images. While we make every attempt to make sure the data we receive is high quality I encourage you to reach out and complain about the quality so that they start sending us higher resolution photos.