To choose the best compositing software, you should consider what type of compositing you need to do and how much you want to spend. If you are looking to composite two-dimensional (2D) images together, then a photo editing program would probably work well for you, though you might consider an illustration program as well. On the other hand, if you want to composite video together, especially if you are interested in using three-dimensional (3D) works, then you might consider a 3D compositor or a video editing program. You should also consider how often you are going to be using this program, as some compositing software can be quite expensive.
Compositing software typically refers to programs that assemble different types of media, usually visual media, together into a final product. If you are looking for a program for compositing still images, then you should typically consider a 2D compositor for editing photographs or creating illustrations. These programs often have different tools and can create images as either vector or raster images. You should consider what type of images you want to work with so you can choose the best compositing software for your needs.
If you are interested in compositing video or more complicated images and works, including graphics you create in a 3D imaging program, than you should consider more elaborate compositing software. These programs are usually 3D compositors that can assemble layers in more elaborate ways and allow you to better control the compositions of video and other moving images. You might also consider a video editing program to accompany your compositing software to more easily edit and change video clips before or after compositing. This all depends on your individual needs, however, and you should consider the investment necessary for owning or licensing such programs.
Many of these compositing software programs can be quite expensive, so you should think about how often you are likely to use them before choosing a program. If you are going to use compositing software on a nearly daily basis for professional work, then you should look for a program that is powerful enough for your needs and consider the cost to be part of your work expenses. On the other hand, if you only want a program for amateur or occasional use, then you might consider software that is less expensive. There are some fairly powerful, inexpensive or even freeware programs available for compositing, though you should ensure any such program includes the functions you require.