So basically I have an image gallery site that I'm starting up. What I'd like to do is have 3 or 4 rows of 4 pictures that are pulled randomly from the gallery and displayed on the sidebar. Is it best to pre make these thumbnails and have them pulled from a separate folder and the linked to the main images... or would it be best to generate them on the fly from the original images? What would be best speed wise? Also, if anyone wants to do this for me, give me a quote through PM - I know there are many free thumbnail creators out there, so all that would need done is implementation.
How about generating them on the fly the first time they are used, then caching them so they don't have to be generated again?