Can't delete photos I transferred from my Computer to iPhone

The "for iPhone" picture file.

You mean a folder that contains these photos that you selected under the Photos tab for your iPhone sync preferences?

Is this a single folder that includes all photos, or a parent folder with multiple folders within that includes photos?

You don't need to delete the photos from your computer.

If you selected a single folder that includes all photos, remove the photos from the selected folder that you don't want transferred to your iPhone followed by a sync. This will remove the photos from your iPhone.

If you selected a parent folder with multiple folders within that includes photos and these photos that were transferred to your iPhone are in a separate folder within the parent folder, remove the folder that contains these photos from the parent folder followed by a sync.

The iphone has a folder/album called "Photo Library." This is always going to be there. It is the way Apple's photo system works.

You should also have the folders/albums that you selected to be on the iphone. Photo album will contain all of the same pics as your folders. They are not on your iphone twice. You can simply view the one copy of the pics from two different places. There is no way or reason to get rid of this.

All photos transferred from your computer are stored in your iPhone's Photo Library.

If you select a single folder of photos to be transferred, you will have all photos in the Photo Library and in the named folder, but the photos are not duplicated. The photos in the named folder on your iPhone include a pointer to the original photos stored in the Photo Library.

You can have a parent folder on your computer that contains multiple folders within that contain photos. When selecting the parent folder under the Photos tab for your iPhone sync preferences, all folders within the parent folder that contain photos will be transferred and stored in your iPhone's Photo Library.

This way, you can view the photos in a folder only by selecting the folder under Photo Library, or view all photos in all folders by selecting Photo Library.

The photos in the folders are not duplicated, although it appears so.

You can't delete photos from your iPhone that were transferred from your computer.

What is selected under the Photos tab for your iPhone sync preferences?