try zen cart. google it

GIMP is free, but I dont know many professionals using it.

The reason professionals choose photoshop is because adobe provides good support and future development. As a free product, GIMP cant provide that as good as Adobe.

isnt microsoft publisher for brochures? i havent used it for web at all, does it export HTML or any other website files?

yeah just upload the files to a web host.

you can try both. they would work, as long as the folders are in the same places.

there are a few ways.

reduce content
optimise images
host images somewhere else

frontpage is outdated. its now known as expression web.

is that your site?

yes, its wordpress. and you add a gallery plugin.

delete the white background, and save as png