The easiest way:
1. Get a image that is bigger than 800x100 and use it as a banner (resize and/or crop if needed)
یا make it online.
The hardest way:
1. Get photoshop یا something like that
2. Start a new project
3. Enter the measures (800x100)
The اگلے steps will only depend on how good آپ are with it 4. Select a few تصاویر آپ want to use and open them (it won't affect your project)
5. Chose the part of the pictures آپ want to use (If آپ wanna use the entire picture, just copy and paste it there)
6. Add a few effect یا text
7. Save it as a image file (.jpg, یا .png)
the hard way is way مزید complex than that and requires a bit of skills around an image edition program (which requires a lot of practice and time), so if آپ want something quick, go for the easy way.
Plus, check
link for مزید help.
