Gordon,
You're not on your own on this, it is very annoying. I've resorted to producing two sizes of image for web presentation (800 and 600 on the longest side) but even using the smaller size here can be problematic.
There are two solutions I can think of. If you are viewing the site using Firefox, you can right-mouse click on the image and select "View Image" from the context menu that pops up. However, this is far from ideal. A slightly more elegant solution is to add a "View Fullsize" link as a comment below the image, just as I've done in response to Tim's comment on this image of mine This will open the image at it's full size in a new window. You have to save the image first of course so that you can get its URL. Hope this helps some.
- Thorsten.
EDIT - I've just added such a link to the last image you posted in your gallery to better illustrate my point.