Latest release of Elgg 1.9 is 1.9.7. I would suggest to update at some near time in future. Even better, I would suggest to update to Elgg 1.12, i.e. 1.9 -> latest 1.10 -> latest 1.11 -> latest 1.12. You will get at least bug fixes, some new features and performance improvements by doing so. Also, there shouldn't be any issues with compatibility of 3rd party plugins, i.e. almost all working on Elgg 1.9 will also work up to 1.12 and in the rare cases a plugin wouldn't work there might already be an update available.

Regarding the issues with the images:

• are there any log entries that might explain what's wrong?
• it could be some file of Elgg or a plugin missing or being corrupted. This could have happened on an update. It could help to copy Elgg and the plugins again on the server to add any missing or incomplete files. If the reason for the image issue would be due to a missing file, the server logs would contain some entries for sure.
• The problem might be caused neither by the blog plugin nor by Tidypics. It could be another 3rd party plugin used on your site that is causing the problem. It might help to disable all 3rd party plugins apart from Tidypics to find out if any of them is causing the problem.