1.) Go to ImageShack.us (I advise joining so you can keep track of your images and find them again if you loose any of the addresses) and host your first image.
2.) Once you have done that, ImageShack will give you 8 web addresses, highlight the 3rd, titled “Thumbnail for forums (1)” and copy it.
3.) Paste the address into a text document, then upload the rest of your images and paste their addresses in the same document, save the document when done.
4.) One at a time, paste these addresses into your gallery thread. Only type one space between each address, DO NOT start a new paragraph between each one.
5.) Once you have your gallery how you want it, post it. When you do, you may notice that a scroll bar has appeared on the side of your gallery. To get rid of that, take note of where each line of thumbnails ends, then go to edit your gallery again and start a new paragraph in those spots only. Post it again, when you do, the scroll bar will be gone.