As Matthew pointed out the complete list of options is listed in the Graphics Guide (grfguide), i.e. the manual of the graphicx package. Similar effects can be achieved using the macros provided by this package, i.e. \scalebox, \resizebox, etc. There is also the adjustbox package which provides the missing \clipbox and \trimbox as well as the general \adjustbox macro which accepts all \includegraphics options and applies it to general text.
However, all effects are applied to the original image as part of the rendering done by the viewer software. The image is still included in its original form. You shouldn't see the package as an image manipulation tool. Rendering it as B/W might be possible as some PDF commands, but graphicx doesn't include such. Also the resolution is not affected. Both should be done using an external image manipulation software.
Flipping an image is possible. Try scale=-1. If you only want to have it flipped in the X- or Y- coordinate you need to place the \includegraphics command inside a \scalebox which accepts an extra optional argument. There is also \reflectbox{...} which is the same as \scalebox{-1}[1]{...}. Unfortunately, \includegraphics doesn't support that directly.
