Note that I can only use ASP.

Is it possible to prevent hyperlinking of images(as to prevent people stealing them)?

Can I(in regular ASP) dynamically resize images?

Can I dynamically add a watermark(just like a small label at the bottom)?

Can I(in regular ASP) dynamically resize images?
Can I dynamically add a watermark(just like a small label at the bottom)?

Not from a standard install

Is it possible to prevent hyperlinking of images(as to prevent people stealing them)?

Yep, provided you can have a custom 404 page.

http://evolvedcode.net/content/code_antihotlink/

"Is it possible to prevent hyperlinking of images(as to prevent people stealing them)?"
yes.set you response type.

Response.ContentType="image/gif"
Response.ContentType="image/JPEG"

"Can I(in regular ASP) dynamically resize images?

Can I dynamically add a watermark(just like a small label at the bottom)?"

yes.use adodb.read them out.and then you should known the file format of gif/bmp/jpg.and then use some algorithm to add or delete data and then write to the file.
of course,this is too difficult.
so i suggest that you can download and use "aspjpeg" module or other like it.
how to use it:
http://www.aspjpeg.com/