home page is loading very slow

I ran a test on Google PageSpeed Insights and have attached a screenshot of the results. The results for the mobile (20/100) were slightly worse than they were of the desktop 25/100

Itemized list of “should fix” items:

Optimize Imges
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Leverage browser caching
Minify CSS
Minify JavaScript
Minify HTML

When I ran this by the developer, he said there was nothing that could be done about this, besides resizing the main image. Seemed like a strange answer to me. Do you have any suggestions?

Please see attachment for screenshot and blog name (blog.cityofzdesign.com).