For another Blog that filled with images, I've setup Thumbnailer Extension (original at http://blog.data-worx.de/page/Extension-Thumbnailer.aspx ).
But it's appears that JPG receive terrible quality when creates resized images, so I updated this extension a bit.

With a lot of respect to developers of this extension - I want to notice that this is just my little contribution. I currently don't have enough time to contact this extension developers, and write a good fix. In case someone needs this fix, I'm attaching patched cs file.

Thumbnailer.cs (24.72 kb)

Currently you should search for string: "int JPEGQuality = 100;" and change quality value as you like. I think later we need to change this to the parameter in [Thumb].