A couple of things though - firstly the icons you've used refers to your languages version of Program Files so people with other languages will just see the default smiley faces - easily remedied though.
Secondly, the functionality to add files to ImgBurn is dependant on the latest version - it doesn't work with anything earlier than 2.4.0.0 as far as I can tell.
I think a "Burn Image file" option is the main thing missing.
Additionally: "Create Image File from disc", or perhaps even, "Create Cue File" for example. ImgBurn has a lot of nice options to explore.
Also, I can't make it to work on Win7 x64. I get the 2 generic smiley icons, and the toolbar won't install/appear properly.
You do realise you can edit the toolbar yourself and add any feature that ImgBurn supports from the command line ?
As for the Windows 7 issue it's probably related to the button being configured for the default Vista installation paths rather than the Win7 64Bit ones. Again, you can edit the buttons to fix this.
FWIW, on Windows 7 you can burn .iso files by double-clicking on them by default.
You should be able to tell ImgBurn to do the same thing if you want to use that instead. I don't have it installed right now to look-up its command-line though.