Hi there!
WP Offload Media Support Team here, Thanks for reaching out with your query we would be happy to assist
WP Offload Media can only offload media files that exists on your WordPress Media Library. If the images you’ve linked to your posts do not exist on the Media Library then I’m afraid WP Offload Media won’t be able to handle and offload those files.
You’ll need to upload those images first on your WordPress Media Library for WP Offload Media to notice and offload those files.
Please note that both WP Offload Media Lite and ‘Pro’ can automatically offload newly uploaded media files. However, WP Offload Media ‘pro’ can also offload existing media files while WP Offload Media Lite cannot.
More info here – https://deliciousbrains.com/wp-offload-media/upgrade/
We offer a 100% No-Risk 60-Day Money Back Guarantee. If for any reason you are not happy with our product or service, simply let us know within 60 days of your purchase and we’ll refund 100% of your money. No questions asked.
https://deliciousbrains.com/wp-offload-media/pricing/#guarantee