How do i make a jpg 200x150 for the adveriment flash i just bought..

You can do this quite easily, we use high-end professional software, however the same can be achieved either by using a server-side script (more for advanced users), or a client-side program. Here's a list of different ways to achieve the same result.

WEBSITES:
Resize Images online - Allows custom settings to be entered.

Small JPG.com :: Resize your JPG images online ›› Resize - Probably the best one we've seen with width and height adjustments.

MOSTLY FREE SOFTWARE:
Jpg resize free software by Vincent W and others - List of various software programs that will achieve the same results as above, but installed on your own computer.

Commercial Software:
Adobe Photoshop - Professional Image editing software - Price: $999.00
Adobe Fireworks - Professional Vector based image editing software - Price: $299.00