Iím regularly asked to post larger images than I typically do for internet postings, which is around 650 pixels on the long side for the typical 2x3 aspect ratio.
While I'm honored that people want a better look at my photography, I simply can't do it because I market my imagery (even though now retired) and since I sell only digital files via the internet (not prints) and itís a sad truth the internet is infested with image thieves (both casual and professional), to give them anything worth stealing would be irresponsible on my part because my imagery would then have no monetary value.
When an image is posted to the internet, for all intents and purposes it has been released to the public. Even if you copyright it, someone can still copy and use it however they see fit and even in the unlikely event you discover this copyright infringement, the average person has little practical recourse. Suing someone even in your own country, let alone in a foreign country, would simply be too time consuming and expensive to be worth the effort. Therefore the only logical thing a person can do to protect themselves is to simply not post anything usable in the first place.
Even posting a 650 pixel wide file makes me nervous as this is actually enough resolution for some video usage and quite a bit of website work and anyone who posts imagery at a higher resolution either considers it to have no monetary value or, and to put it bluntly, they are naive.
If you find the image size I post at is too small, web browsers do have a zoom function that allows zooming into web pages for a larger view and while it wonít increase the detail in this kind of imagery, it will make the images easier to see. Not a perfect solution, but an easy alternative.