posting ebay pictures

You can select thumbnails in the Organizer and choose:

File >> Export As New

Export to a Picasa folder or a new folder and then browse or drag them into Picasa.

I had just a look at ebay's requirements:

Adding pictures to your listing

I would forget about Picasa. The problem is simply to use the Ebay downloader to upload files in a subfolder in your computer.

The download process is described in that link.

To prepare the files and put them in a subfolder for upload, the organizer is the perfect tool.

- you can manage your files with your own keywords, create organizer albums (sort of playlists for selected and sorted items) for easy retrieval

- If you create a selection or an album for a batck of files, you can 'export to new' files in a new subfolder. The export feature lets you choose the size in pixels and jpeg compression quality as well as rename the files in a single operation.

Without the organizer, you can also prepare your files to the right dimensions and quality from the 'process multiple files' command in the editor; that will also put them in a subfolder ready for the Ebay downloader.