This makes them more accessible and easier to maintain, as updates can be made on the server side without requiring users to download and install new software.
There are many different techniques
Cropping and resizing
Adjusting brightness, contrast, saturation, and hue
Removing blemishes and imperfections
Sharpening and softening images
Applying filters and effects
Changing the color of specific elements in an image
Adding or removing objects from an image
Creating a blurred background to emphasize a subject