If you are using jetpack and your images are not showing properly then try these methods.
01. Check if you have hotlink protection enabled for your site. If enabled then add these urls to the protection exclude list.
I mean you need to permit this URLs to load images.
02. Have you recently updated from http>>https ? I mean if you have started using the ssl certificate on your site, then you need to add the exclusion on the hotlink protection area.
03. Try deactivatin the photon plugin for WordPress Jetpack. On this scenerio your images will load from your server. Might be little slow.
04. Try to deactivate the Jetpack plugin itself to check if the problem is persistent.