Pressing shift while hovering your mouse over them should do the trick.Ashlee2810 said:
It would be great to increase the image sizes that show a preview, as a setting. I like to see the image before I get it but am having trouble seeing some clearly, good suggestion that I hope to be added.
(I only found out accidentally about this after having used this site for several years already. I wonder how many other people don't know about this feature)
Ashlee2810
Change preview size of images when browsing posts