move images for benchmarking-mortgage-underwriting-agents to correct dir

[mtoles]

move images for benchmarking-mortgage-underwriting-agents to correct dir

[Alex-XJK]

This PR has the following two issues:

1. During the process of moving the image path, only the deletion step was committed by the PR author; as a result, we discovered the images not found issue during my local testing. (Resolved in d5329cd)
2. Lingering issues from Add benchmarking-mortgage-underwriting-agents blog post #69: Blog-specific style code was incorrectly added to the global file, which could have been resolved with a local style declaration; image references were not implemented as specified in the README; and images were placed in the wrong directory. (Resolved in a33531d)

To minimize back-and-forth, I will assist with the changes locally. However, please note that future PRs that do not follow the README guidelines will be rejected outright.