You will need to make sure the images you add to your signatures are hosted in a publicly accessible location so anyone can view them.
There are freely available services that can host images, you could create a Google Site, or use Google Drive to store your images.
To do this in Google Drive, you should upload the images to your Drive, change the visibility of this to be public on the web, and then add the following URL image to your signature template:
Replace the FileID with the the two-part string of characters in between /d/ and /edit or /view from the URL.
Note: You can check this URL is public by opening an incognito browser window (Ctrl + Shift + M in Chrome) and entering the URL of your image into the address bar.
You could also use Google Sites to host your images:
1. Create a new Google Site
2. Upload the images into the new site
3. Ensure that you have made this site public within the sharing settings (https://support.google.com/sites/answer/98182)
4. Then save the site, right click on the image and click copy image address.
5. Paste this URL into your Ancoris Signatures.