EXIF data

If you are worried because of the http://www.hoax-slayer.com/cell-phone-pictures-privacy-risk-warning.shtml that exploded on all our walls yesterday...

Depends on the program and the preferences for both questions. There are free programs which will remove just the exif.

If you paste a photo into a new file, most of the time the EXIF data will be that of the new file, i.e. blank. (I do the opposite - I paste my stitched-together panoramics into a resized copy of the first picture in the set, to apply all its EXIF data.)

You can also save files without metadata in Photoshop and I'm sure in similar programs.

I just checked using an old version of Photoshop (CS). Exif metadata from the camera was replaced with Exif data from Photoshop. If you want to check this stuff yourself, I recommend using http://rsbweb.nih.gov/ij/. It's a free (and quite powerful) image analysis software. It also comes with an http://imagej.nih.gov/ij/plugins/exif-reader.html, which will summarize the Exif metadata for you.

Save your file as a .png, it will lose the EXIF data.

If I cut and pasted part of a photo and saved it as "NEW" The new file would not contain the original file's EXIF data in this case (but would contain some new EXIF data generated by Photoshop). If you open a file, modify it, and resave it, it may contain some EXIF or none at all, depending on how it was saved: Photoshop's "Save For Web" strips out all EXIF data; a plain "save as" includes some EXIF from the original photo (including the camera model and I believe location information) as well as some photoshop-specific data. You can also use programs such as http://imageoptim.com to strip EXIF data from existing files.

One easy way to strip the EXIF data is to do a batch conversion in Irfanview (which everyone should have anyway). While I have no doubt that Photoshop can do the same, Irfanview is free and the conversion process is very straightforward (there are checkboxes for removing EXIF and other camera data from the image). You can also do things like re-size the pictures or change the filename (which can be useful as often the filename will include things such as the time or latitude/longitude when the picture was taken) at the same time if you like.

If you have a copy of Microsoft Photo Editor (the old one from like Windows 95 or so, not Microsoft Office Picture Manager), it seems to strip EXIF data with any modification and saving of the file. I've always moved a copy onto my newer computers and it seems to work fine.