The software used should not make much difference.
I think the quality loss happens when you convert the image to the jpeg or gif format.
Everytime you open and save a compressed image format, some image data is lost.
It is recommended, that you perform all editing on an image while it is in the tiff or bmp format, and then compress only the final image to the jpeg or gif format.
And, yes placing an image into a document, then onto a web page from the document WILL result in noticable loss of image quality.
I use both U-Lead Photo Plus, and Adobe Photo for my image scanning and editing, and have seen no loss in quality UNTIL I re-edit an image saved to a compressed format.
Another thing that may be happening, is that either the web host, or the web page software may be stripping down the image to reduce the file size. Any tools used to reduce the file size of an image will reduce the image quality.
Chas