As recently as a couple of years ago I was writing my own custom AS3 based slideshows for showing off my own photos online. Back then you simply couldn't rely

As recently as a couple of years ago I was writing my own custom AS3 based slideshows for showing off my own photos online. Back then you simply couldn't rely on a browser to resize a photo correctly outside of Flash, which made it impossible to support different client resolutions without storing a ton of copies of the photos on the server or doing dynamic server-side resampling, both of which had their own drawbacks. If you left the photo resize up to the browser you'd end up with a horrible non-resampled mess if the photo was shown in anything other than 1:1, whereas in Flash it was trivial to display a bilinear resampled version that looked great at any size up to and including 1:1 of the original photo. I think at this point the usage of Flash is mostly just inertia... it is done that way because it was always done that way. But it was done that way for a purpose. Web browsers sans Flash were horrible about displaying resized images until relatively very recently.