I thought I recalled seeing suggested dimensions posted somewhere but cannot locate them. I generally resize to a maximum width (or height) of around 800 - 900 and retain the proportions.
Given that most folks probably use 17-, 19-inch, or larger displays you might get away with larger sizes. If an image requires scrolling, I'd reduce the size.
I think there is a limit on file size if hosted by FM - perhaps a subscriber to those services could help out here? Do not post RAW images.
The exif data comes along with the jpg. I think (but am not absolutely sure) some sites such a flickr, etc, strip out the exif, if it was there to start.
Although FM says 640 on the longest dimension, I think 800 is more reasonable and fine for virtually all viewers. I will sometimes do about 1000 wide. You want to prevent others from having to scroll.
While I cant find it, I think the Image Upload feature restricts uploaded file sizes to 215K. In practice, most files up to 250-275k will post successfully.
Try to post 1-3 related images at a time, max. Otherwise you are less likely to get detailed responses. I personally do not look at galleries folks link to. Just to many things to look at on FM to go that route.
Finally, you can always offer a link or email a large photo if there is special interest.
