Be sure your new file has the proper format extension, too. To save your file in JPG format, you should be in RGB color mode. Adjusting the File Compression allows savings in disk space and transmission time, with a potential degradation in quality of the image. You simply select the one that looks good at the smaller file size, then save. Also, for visitors not using an Image Capable viewer, according to NY State law, you must use the ALT tag.
Resolution is the amount of information an image contains.
This information comes together in the form of pixels. Scaling refers to the physical size of your image, in inches or pixels, not to its resolution size. When scanning images you need to keep in mind the resolution of the output device through which your images will be displayed. Different output devices use different methods to display image data and have different limitations on their output resolution. These factors need to be taken into account when you scan images.