Hey! Thanks for the detailed review, I'll try and answer all your questions.
- You can add a whole folder of images to Tabliss! Simple change your background to "Upload Images", click "Browse", and select all the images in your folder. - Unfortunately you cannot have Tabliss, and the default Firefox new tab at the same time, due to technical limitations. - I like the idea of other images sources, I am looking into adding some more in the future :) - For the temperature issue, could you send a screenshot of your Weather widget settings to email@example.com and I'll see if I can find your issue.