Create a nopCommerce Template

I am using a standard template (NopRoot Bootstrap theme (Free)) and I am quite happy with the layout. The tempate is available at [login to view URL] I need changes made to this existing nopCommerce template to display images consistently either as square images or oblong so I can upload a single image which can be used for both product thumbnail image and product main image. Currently my square images are either being stretched for the thumbnails, or if I change it to oblong images, they are being squashed for the thumbnail or looks pixilated for the main image. In the software "media settings" one can only change the larger of the image dimensions. I wish to have consistent dimensions for all product images (thumbnails and category images one size, all other product images a larger size) in order for it to display well on my website (preferably square). The images which I have used on my previous website are 460px by 460px (72 dpi). But this can be changed if it will improve the website's appearance without grinding the site to halt whilst downloading images. I would also like the elements on my website to be shades of green instead of the black and blue in which this template is released. The background should remain remain white. I would prefer to make contact with a local english or afrikaans speaking developer, since it simplifies communication if I need more changes made to the website in future, and I don't want to struggle with a language barrier. My website is [login to view URL] if you would like to see what I am referring to.