Righty, by the sounds of things the images in question are JPEG images. One rather nice feature with JPEG's is that you can compress them, reducing the filesize and thereby reducing the time it takes to load.
The problem is that if you increase compression, you decrease image quality. This sounds a little bit like what's happening here.
To solve this, you'll need to rummage around in Image Composer for a way to adjust the compression. I can't help you much more than this as I don't use that app (never heard of it until now, to be honest). My first bet would be to search the Help files...
For the second part of the question, it appears to me that you are immensly confused at the difference between Frontpage and Image Composer.
Frontpage is for making webpages. Image Composer, by the sounds of things, is for making or editing pictures. IC won't have options for tables, marquee's etc because that's not what it was designed for.
If you want to put this picture on your webpage, you'll need to save the image(s), and then use FP to insert the image(s) into the page.
I hope that helps