This will let people post huge pictures which will display as thumbnails up to 300 x 300. Clicking the picture takes viewers to the full size image on Photobucket or wherever it is hosted...
This will save a lot of resizing, hosting the picture twice (small and large) or having cut off screenshots posted.
there is an issue with using CSS inline styles or html width/height attributes to create thumbnails... since both options are entirely browser rendered, the full size image must be pulled down by each user, just to render a thumbnail... if locally hosting the images, it leads to a bandwidth spike, if remotely hosting, it causes slow loads for those with slow connections (yes, dial-up still has significant market share) or bandwidth caps. it is a better solution to use a PHP script, with GD backing to, when the page is created/accessed, see if there is a thumb on file, and if not, create one on the fly and store it... that way, you can enforce filesize limitations with a strict resize/compress script to keep your bandwidth down, and still have real thumbnails, to keep the user's bandwidth down.
