I have used Deduper and love it. Opens up a bunch of zipped files and automatically removes the formats you don't want.
As for the second question. Embird Basic is nice to have. It has a lot of functions you don't find in every customising software, it is reasonably priced, easy to use and there are a lot of users here who are willing to help when you have a question / problem.
Take a look at Embrilliance and it's counterpart Thumbnailer. Affordable, easy to use and good customer service. Hugs. Nan W
I use Floriani's Image Maker, which is due to have a big update any day now. It works in the background - you never really notice it. When I got it maybe four years ago, it was $99 or $69 at a Floriani event. (Always go to an event to purchase the big stuff. like their digitizing software - deep discounts.)
I use Wings' My Editor all the time for removing parts of a design...parts I feel unnecessary for the item I am making. The software is free...I've had it for maybe 10 yrs. if I can coach you thru the deleting steps, just pm me. You can undo all your changes before renaming & saving. I couldn't be w/o it even tho I have PEDesign software. A great little program.
I also use My Editor. For the moment it does everything my basic skills need.
I have had Deduper for years and years. I am not sure I could manage without it, I am so use to it. But, I know nothing about other such programs, so I can't really tell you what is best. I do know DeduIper has gotten expensive since I purchased it and on occasion I will find it on sale. So, I am happy I purchased it long ago, as so far, updates have been free. It does have to be registered for only one computer. So whenever I have had to switch computers - I have had to contact the company to do that. Hope that helps!
I should have followup with your second question - I use Embird, which will let you do many things to a design. It has a few trial which I encourage you to try!