The resize should be automatic for bike forums to make an image smaller than 100 kb. Nothing in the menu.

However, the system might choke on very large images, or perhaps some image encoding. So, I normally use some 3rd party image editing software on my PC (GIMP) to shrink the images to about 98kb using both image size & lossy compression.

There are 3rd party image hosting programs you could use, and many people like. However, they frequently delete low traffic images, and a large hosting service just blanked out all hot-linked photos, so that is always a risk.