I have very little understanding of creating my own webiste, but have created a webpage using the plusnet website builder. I wish to use the webspace for uploading pictures that i can link to, which i can do, but...when i upload 1024x768 or 800x640 size jpegs, they always revert to much smaller sizes (e.g. 600x450 )...how can i upload pics to be displayed on the web as 800x600 or 1024x768?
If you are uploading your pictures as 1024 x 768 then that is the size they are.
What is probably happening is that you are using I.E. 6 and this itself tries to make you pictures fit inside its own window.
Do you see a small Icon appear bottom right on your picture after a few seconds. If you do then click on this and it will open it up to the full size.