Thank you for your feedback!
We reproduced the black screen(audio only) issue with some particular AVI and WMV files. And we'll fix it in the next few updates. To confirm the behavior is caused by the same bug, we hope you can share with us(firstname.lastname@example.org) the logs or a AVI/WMV file.
To send logs, you just need to click SKYBOX's Global Settings(the gear icon), click the BUG icon in the upper-right corner, and send us a bug report attached with logs(tick the "upload logs" box).
Besides, you CAN change the Loop settings to Shuffle. Please check this FAQ article.
Regarding the suggestion on image viewing, we'll have a discussion.