Here is a video that walks you through changing the thumbnail image of your content.
To change the image associated with any document, image, link, or video in your OneMob library...
1. Click on the library icon on the left side of your dashboard.
2. Click on the content that you want to edit.
3. Click on More.
4. Click on Change Thumbnail.
5. Add thumbnail text by typing in the box labeled Thumbnail Text.
6. Select the alignment of the text by clicking on Top Left, Top Right, Bottom Left, or Bottom Right in the drop-down menu.
7. Select the thumbnail image from your OneMob library, your device, or by generating a new one. If one is present, delete the existing thumbnail.
8. Choose to add a watermark.
9. Choose to add a color.
10. Click on Save.