I have been looking for an extension like this for a long time! I've tried others, but just after 5 minutes I'm impressed with the extension. The free version gives a basic user exactly what they need a way to upload an image, resize, and save. If you need more features you can buy the pro version for about $20 bucks (USD).
Message to the developer: Anyone that complains about this extension are just haters! Just like it's almost guaranteed that the sun is going to come up everyday, HATERS will HATE everyday. Great job and do not let any negative reviews bother you.