Two useful features would be nice to have

Hello,
I read that this plugin is not abandoned and soon new version coming.
Can you consider add two following features:

1. to be able to choose timeframe when to regenerate thumbnails (for example March 2015 only, not entire site)
2. Ability to just delete legacy thumbnails files from the disk of those image sizes that are not defined in WP anymore, without regenerating valid thumbnails.

I think that would help a lot of people working with a large website with many images accumulated in past years.

If you need a beta tester, please drop me a line.

Thank you very much!