You could add HTTP image source to shorten URLs that you are using for the integration.
Login to your Pixboost account.
Click on "Add source" link under the "Images Sources" panel
In the appeared form set Type to "HTTP" and fill in the details
Alias is a unique identifier of the images source that will be used in the URL when calling API
Images location is a URL where the original images stored
Click on "Add" button and verify that the source has been created