Am I doing too many resizes?

[eluser]Phil Norton[/eluser]
[quote author="fesweb" date="1226129595"]

Matt G.
- Also, FYI resizing from 300dpi (most cameras output 300dpi images) down to 72dpi (screen resolution) takes ALOT more memory than resizing a 72dpi image. ~228 times more memory is used when resizing a 300dpi image down to a 72dpi image, than resizing a 72dpi image.

Is this true?

I've always gone on the theory that pixels is pixels. A 900px x 600px image at 300 dpi should be the exact same size as a 900px x 600px image at 150dpi or 72dpi. When not printing an image, dpi essentially seems to be meta information.
[/quote]

You're correct. DPI is only useful for print (hence the use of "inch"). It's all about the number of pixels, not the resolution.