This particular file extension is a specific one and it requires additional configuration, depending on your exact environment. For example, can you please check and confirm that you added this extension to allow file extension in the target environment?
UPDATE: the CMSImageExtensions web.config key shall not contain the SVG or WEBP extension - otherwise Kentico tries to apply some image processing on these and since they are not supported, staging will fail with the error. The solution is not to use this key.
< staticContent >
< remove fileExtension=".svg"/ >
< mimeMap fileExtension=".svg" mimeType="image/svg+xml" />
- the Settings application, in Content -> Media category, into the "Media file allowed extensions" field
- the Settings application, in the System -> Files category, into the "Upload extensions" field
You may also need to add SVG support on IIS to each site as described here.