The Keyboard Maestro Forum Search isn't bad, but it's pretty basic. I tend to use it on a first pass when I'm looking for something, but I frequently end up turning to Google.
Many people don't know you can do site-specific searching with Google. It's easy:
I have never seen any broken images, so I don’t know why you are seeing them. Given the reports seem to indicate they appear later, perhaps it is some sort of caching issue? I believe Discourse moves images after they are “committed” and then adjusts the post, so its possible there are bugs in that part of Discourse. You could ask on meta.discourse.org to see if it is a known issue.
I’m finding the same issues, only the images don’t tend to appear later. However if I view the source code and extract the URL for the image and open it in a new tab I can view it. I might try a different browser .use Chrome currently.
Update: I think I may have found the reason. Most of the images posted to the forum I can see, it’s just some that don’t work. Looking at the source again the ones I can see are all .png and the ones I can’t see are .tiff, so probably best to post in .png format.
If people will report broken images or TIFFs on the forum to me I’ll fix them where possible, but please message me direct and keep irrelevant traffic off the forum.