ergophobe - 11:18 pm on Jun 8, 2012 (gmt 0)
Okay, first things first: I feel your pain. Just did a similar thing and getting the images into Drupal was just nightmarish. I only had about 500, and after a few tries at creating an import script, I just gave up and literally hand-imported into Drupal (meaning I added the images through the Drupal interface).
This is extremely painful, except that I don't have *that* many pages - probably average 10 images per page, and with a multi-upload plugin, it wasn't that bad in the end.
All that to say, I'm not sure I can really answer your questions, because I gave up and just did it the Drupal way.
Stopping Drupal from duplicating (resampling and recreating images)
The derivative images should not get created until they are actually viewed - so if your theme isn't calling for them, the images should not get resized and resampled. This includes the admin side, though, so if you have thumbnails appearing on the admin side, the thumbnails will get generated. You can't stop that without some serious theming on the admin side and that will be painful.
Is it a storage issue? You can simply choose not to use the resampled versions and theme it to use your custom thumbnail.
>>The files are there but they just don't show.
You have them in the file_managed and the file_usage tables and you also have a field_data_#*$!xx and field_revision_#*$!xx for the image field and have those all linked to the node? That's pretty complicated to get right.
>>width=0 and height=0
Do you have the dims set in field_data_#*$!xx and field_revision_#*$!xx ?
As a general observation, you might need to do something like create a "field collection" where you upload the thumbnail and the main image separately and link them together at the theme level.
I set up mine so I could have a "teaser" image that is custom if I have one, but otherwise takes the first image from the gallery. Similar (though much easier) problem. It's at the theme level that I decide which image to use for the article teaser.