What does a thumbnail program do?

[CaribeJoe]

In Admin CP I selected a thumbnail program.

I also defined max for both the image size and the  thumbnail size.

When I open the dialog to up load a photo, I am offered the photo path and another for a thumbnail. That does make sense to me.

If the purpose of the thumbnail program is to create a thumbnail autmatically from the image, why must I offer a thumbnail and not simply the photo itself?

And if the thumbnail progam does not create thumbnails, why bother with a thumbnail program?

[V@no]

When I open the dialog to up load a photo, I am offered the photo path and another for a thumbnail. That does make sense to me.

If the purpose of the thumbnail program is to create a thumbnail autmatically from the image, why must I offer a thumbnail and not simply the photo itself?

sometime I'd prefere create thumbnail from just a part of the image, for example I want be showed only face of a person then whole image where u cant even see that there is a person, because they are too far away. That's the purpose let upload "home-made" thumbnail.
And as u could noticed by ammount of posts where people having problem with creating thumbnails, because of each hosts individual configuration. Some host dont even support any graphic convertion tools.

And if the thumbnail progam does not create thumbnails, why bother with a thumbnail program?

if it doesnt work for u, it doesnt mean it doesnt work at all

[CaribeJoe]

Some host dont even support any graphic convertion tools.

As I said before, I own the serer. It's a Unix Red hat with the latest PHP and MySQL.  Exactly what support must I provide?

[V@no]

I already answered this in another thread about GD/GD2/ImageMagick