You are unable to select images like Mail because of a recent change in WebKit's user agent style-sheet. We now add "-khtml-user-select: element" to images and other elements to improve normal browsing and editing. This change was introduced in 10.4.6.
We also fixed khtml-user-select: none to have the following additional behavior (that matches Firefox's implementation of the property as well)
(a) If you mouse down (or click, double click, triple click) inside a "none" region, the selection should not be cleared or changed
(b) If you drag from within a "none" region out to a selectable region, no selection should be changed or started.
This change added a new value to khtml-user-select called "element" that is used for any object that should have the behavior of (a) and (b) above (but that is selectable aside from that). This includes images, links, buttons, and so on. This fixed the big contenteditable issue and selection is no longer cleared now when you click on these controls (or on links). This behavior matches other browsers.
You will need to add a author style-sheet that overrides -khtml-user-select this like:
img {
-khtml-user-select: auto;
}