If incorrect preview images show up for your freebie (as they will from time to time), you can prevent this - the system only makes a "best guess". The system tries to identify the preview automatically. It can't "see" the image, and so it can only decide based on:
- the name of the images (it looks for words that often are used for previews like "folder", "freebie", "preview" etc)
- the closeness to the download link it thinks is a freebie (this is a big problem if your images have names like "740692.png" etc because they system has no clue what that means).
The best thing to do it to just make sure that the links to your freebies are "wrapped around" the preview image, i.e. that you have [A LINK TO FREEBIE…][PREVIEW IMG…][/A].
If you don't do this, then this is how the system selects the images. If you have only one image on a blog entry with a freebie, that image is assumed to be a preview. If you have multiple images, the system will either choose one that has indicative phrases in it (like "free", "folder" and "preview"), or otherwise it will select the closest image to the freebie mention, or the last image since often people put the freebie last. Remember that there may be images in your post that the blog host puts there, like "Email This" types of buttons. Quite frequently the names of previews are some random number, so a system doesn't have a lot of information to work with and just makes the best guess it can. Sometimes Feedburner etc will corrupt the image links too which causes problems. I apologise for those cases where the system gets it wrong, but in the vast majority of cases it is correct and I think it is helpful for people to see previews here. Sometimes this can go very wrong though, and if I can I correct the really bad ones. But mostly I don't because there are just too many to go through.
Why are images sometimes blank?
Sometimes images are blank if the reference to an image which is selected from the feed is actually invalid. This happens sometimes in blog feeds but unfortunately there isn't a way for a system to identify this automatically. Try naming images carefully as above.
