Resolution question

[K.ErickPhotography]

How do I know when to adjust my PPI and when not too. I have a Canon 50D and when I import to PS my default setting are 19.8 x 13.2 and 240ppi.

Ive heard when downsizing then you can increase and when enlarging you have to decrease.

Can somebody please emphasize this for me or provide a link so I can read up on this.

What settings should I use for web hosting, emailing, facebook etc? size and ppi??

[teaking]

I would suggest that you dont touch your PPI/DPI leave them alone the numbers that really matter are pixel width and height. for displaying on the web I believe most monitors are set for around 96 dpi something like that and most websites give you some guidelines on there recomended dimensions for an image e.g. 800 x 600 so just resize to what you need and leave DPI/PPI alone.

If your printer requires a 300 PPI/DPI file work out the size of the print eg 8x10 and multiply each dimension by 300 thats how big in pixels it need to be in width and height if your image is bigger just leave it otherwise you will have to resize.

And for web where ever possible make sure your colour space is sRGB unless you know that the people viewing the file have a colour aware browser.

If unsure about anything just put a quick search in on google there is a whole universe of articles on the subject to last you well into next year