Create simple image editor web app for website

I require a simple web app that I can embed on to a page on my website that will do the following: (1) Allow the user to upload an image. (2) The image will then appear and the user will be able to resize and drag & drop a 'bear head' and place it over the top of the image. (3) The user can then save the image (with the bear head) and share it on Facebook, Twitter and Pinterest. Some points to note: (1) It is important that the design of this app has the same colour scheme / integrates well with my website (black and white colour scheme). (2) When an image is uploaded, if the height of the image is larger than 700px in size it will be automatically resized to this size (maintaining the width to height ratio). (3) Validation: - will only allow image formats (i.e. jpeg, jpg, gif, png, bmp), - will only allow images to be uploaded if they are <5mb in size - will require the image to be of at least 300px in height. If any of these conditions are not met an error message will prompt the user to upload in the correct format (with a relevant error message).