-contacting the hosting provider if they made any changes to your account, if images are not blocked by hotlink protection, or if there are any limitations/restrictions, etc.
If that does not resolve the issue, try:
-deactivating ALL plugins temporarily to narrow down the problem. If the problem goes away, activate them individually (one-by-one) to find the problematic plugin.
-switching to the default theme (that came with your version of WP) for a moment by renaming your current theme's folder in wp-content/themes. The idea is to force WordPress to fall back to the default theme to rule out any theme-specific issue.