Some images on one particular website open at a high resolution

When I open images on one particular website they appear too large. If I hit command 0 (Actual Size), they become reduced to the proper size. If I close and reopen them, I have to do the same thing. The command - or + also work. I shared screen shots with the page created in Club Express with the author and hers appeared normal. All of my zoom settings are at 100%. Is this an Apple or Club Express issue?