JPEG file size differs save for web, straight save

[digitalpencil]

Hi,
I'm currently working on a project which will end up involving a lot of thumbnails and therefore I am automating the thumbnail generation process using the handy image processor tool in photoshop.
My problem is, that I would like to obtain the smallest file size I possibly can i.e. jpeg quality '0'.
In a regular save, this reduces quality and still ouputs files of 76K!!! for an 80x60 image!!
If i use the 'Save for Web' feature, it informs me the resultant file size will be '919 bytes' (considerably less despite being both set to the same quality!) but even this outputs an actual size of 4K!

What's going on here? Why is photoshop/my OS lying to me?!?
I'm running OS/X 10.3.9 if that helps at all

Any ideas are very welcome,

Thanks,
Digi

 

[digitalpencil]

Have discovered that the 919bytes to 4K difference is due to HFS+ file clusters being a minimum of 4K.

Still not sure why straight save and save for web result in such dramatic file size difference despite having the same quality applied and the end-result being identical.

 

[jimoblak]

This is also due to the fact that SFW strips out meta/EXIF info from the file. Regardless of the file system, SFW will always make a smaller file. That is the point of SFW.

 

[digitalpencil]

Thanks jimboblak, that clarified things a lot.