My favorite for portfolio "web" uploads is 600 pixels on the longest side at 72 PPI (note: DPI is used to describe dots per inch for printing, though I'd never print at 72DPI). I also use Adobe Photoshop "Save for Web" feature as that feature uses a 216 color palette (cross-platform compatibility) versus 256 color palette, it also discards the thumbnail preview and the EXIF data file, thus a smaller file than a typical jpg (save as vs save for web).
You'll find if you do it this way, your file sizes are normally well below 100K which also makes it hard for anyone to steal your images for publication in print.
That's how I do it, thanks, rg sends!
