Site looks fine, I would add a privacy policy and Terms of Service to cover yourself as a business. When adding a privacy policy, remember to add the 3rd party trackers that are on your site.
To reduce your image size in Photoshop, once you have opened the image go to Image > Size, make sure Constrain Proportions is selected and reduce your image to around 800px width (I think this is a decent size for the image on the web)
Once you’ve reduced the initial size of the image, reduce it’s file size by going to File > Save for Web, muck around with the quality savings to get your image looking decent, then save the file.
After you have saved for the web, just close your image, but do not save the changes (it is better to keep the high resolution file in case you need the image for any print marketing)