Also update image fees on blur

This makes sure that the images fees reflect the current state. For example, if an image was removed.

We could also add debounced requests.

components/form.js

@@ -270,7 +270,12 @@ export function MarkdownInput ({ label, topLevel, groupClassName, onChange, onKe
               {...props}
               onChange={onChangeInner}
               onKeyDown={onKeyDownInner(userSuggestOnKeyDown)}
-              onBlur={() => setTimeout(resetSuggestions, 100)}
+              onBlur={() => {
+                const text = innerRef?.current.value
+                const s3Keys = text ? [...text.matchAll(AWS_S3_URL_REGEXP)].map(m => Number(m[1])) : []
+                updateImageFees({ variables: { s3Keys } })
+                setTimeout(resetSuggestions, 100)
+              }}
             />)}
           </UserSuggest>
         </div>