Auto Video Blog and No Images?

Please help!!!

This is my automated video blog: Auto GPS Units.

It uses the eVid Theme (from Elegant Themes) and, behind the scenes, the MyVideoBlog plugin that finds videos from Youtube that it posts at set intervals.

I want eVid to display every video’s preview image, the large size and the thumbnail size, automatically.

eVid requires the ‘Thumbnail’ custom field and the path to the media folder.

1) Is there a plugin that does this automatically as I don’t want to manually modify hundreds of posts.

2) WordPress copies tiny thumbnail images 120 X 90 pixels and trying to change the dimensions through Settings -> Media has no effect.

I have been pulling my hair to run a simple video blog that runs on auto pilot. Can someone help me on this issue?

Thanks!