Jonathan C said
Other than resolution, the three things that have seen the biggest change in terms of possible images are ISO capabilities, Dynamic Range, and Auto Focus - take an image of a static subject, with sufficient light to shoot at ISO 100, and a limited dynamic range in the scene, and there should not be a lot of difference in an image viewed online.
Take the same two cameras (modern and old) and shoot moving subjects in low light with large dynamic range, and there will be a huge difference in the images.
Understood about limitations of dynamic range and ISO.
Did a shoot earlier this year and, when viewing the back of the camera, I thought 'these don't look too good'. Hmmm... On that shoot I was also surprised that I could use f11 instead of the f4 or f5.6 that I'd expected. Being a dim-witted old git I failed to put the two things together. I'd somehow set the camera to ISO1200. Not too clever on a 450D. Let's just say that the pics weren't worth editing.