Greg - great pictures and the DH museum Chippy looks great! Looking forward seeing the end result.
As for the Sywell picture, it is probably Photobucket that re-sized your picture automatically. Photobucket is doing so with large file sizes. I believe that if you keep the file size below 250kb you are fine.
Wee tip for posting pictures: re-size them yourself to about 800 pixels wide. This is large enough for everybody to see and it keeps the file sizes down to a minimum (for our 56k dial up modem users). It also saves scrolling from left to right to view the whole picture.
Cheers, Berry