There is a difference between image size (bytes), image size (pixels WxH), and resolution (quality). The BikeForums attach limit is on image size (bytes). The problem is, you have an image that is 2288X1712.
You are attempting to reduce the size (bytes) by maintaining the size (WxH) and reducing the resolution.
The result? A large (WxH) crappy looking image.

The average computer screen resolution is between 1024 Wide and 2048 wide. Your 2288 wide image is way overkill for this usage.

Take Mr. Fly's suggestion. First, reduce the size (WxH) of the image to fit a normal screen, say in the 600 wide maybe 800 wide at the most. This reduction in size (WxH) will also reduce the size (bytes). If a 600 wide image is still over the size (bytes) limit ... then reduce the resolution.

I use photoshop and do a "save as" and set the desired resolution of the image without changing the size (WxH) of the image. If I know the image is thread-bond, I set the JPG compression down to 3 or so and it still shows up nicely on a computer screen and the size (bytes) is reduced dramatically.

If all else fails, try displaying the image "in" the post as opposed to attaching an image to a post. This bypasses BikeForum's limits all together however you need to have a little respect for those still with low bandwidth connections. Another reason to resize (WxH) and lower the resolution.

<<< "operator" has directed me to remove the image links. So in compliance ... I have >>>