Crappy thumbnails

I am building a wordpress site using the Total theme by Themeforest.

I am used to having an html site that I built in Dreamweaver and cant’ quite figure out or get used to an issue with what I’m trying to do in WordPress…Crappy thumbnails in the portfolio.

The thumbnails generated in the portfolio are blurry. Awful. I have tried different resolution images including replicating what I see on the theme demo. So far they are still unacceptable to my eye for two reasons:

1. Blurry
2. Cropping…I can’t control where to crop the images (and in fact TO crop them! this thing just squishes everything)

I don’t have a live page yet…because it all looks too awful to my eye.

Are there any plug-ins someone can recommend? Techniques?

My original artwork is 54″ at 300 dpi
The images I loaded to my portfolio are 730 pixels at 72 dpi with the image size in the portfolio set up to be about 3.5″

So…since the shrinking thing looks so terrible…is there a way to set a portfolio item up so that it crops a section of the artwork that I can choose? Or a separate image I can create (like I did for my html site)?

https://www.mushaboomdesign.com is the dreamweaver site I have up right now…it’s a placeholder until I can get wordpress figured out.

Thanks,
Barry