Add full supporting of .ico (Icons) like legacy Windows Photo Viewer

[amymor]

Hello First of all, thank you for reviving such a great project, I've been using JPEGView as my primary viewer for almost 6 years. Simple and powerful.

But you know it's painful to switch between apps just to view different image extensions. I tested about 50 viewers (almost all viewers found on the internet, LOL), but still haven't found anything like Windows Photo Viewer that allows us to switch between images packed in an icon file. (Neither can display an icon file correctly, just randomly display an image. But in Windows Photo Viewer you can switch between them and see if your icon looks good for different sizes and dimensions.)

Concept:

It may not be relevant to JPEGView's purpose, but I'm not giving up hope and want this project to be the best it can be. So i think adding full support of other extensions is a good idea to achieve this goal. I also suggest you to try Luiz Fernando GIFViewer and Xtreme-Lab 7GIF, both of them have many features and concepts that will help you to create a better viewer for GIF animations as well.

Thank you again for taking your time to read this.

[qbnu]

Having that extra pair of buttons would probably be a good feature for all multi-frame images. And keybinds that always skip to the next file and not the next frame of the image.