Social Marketers - Would you use an auto watermark and resize service?

Hi,
I am building an online service for myself and wanted to get your thoughts if it was worth making public.

Would you use an online photo service that allows you to upload your post image (also offers a collection of free stock photography and fonts)

It would include a simple online photoshop style image editor for fixes, brightness, and adding that high contrast professional look along with adding text.

The service allows you to simply make your post image, automatically adds your brands watermark, and resizes your images ready to post to the different network sizes - I.E Facebook, instagram, etc.- it allows custom image size outputs to generate as well.

The service can work as an api with say hootsuite or you can use it as a stand alone so you can publish it upon generating it or scheduled post time within the system.

I personally am tired of having to watermark all my images and resize them, I find it takes a lot of time out of my day. Is this just me or would there be a demand for my tool?

So would marketers use this? If so how much would you pay to have this tool? There will be no limit on amount of posts or anything like that just a simple monthly fee for unlimited use.

I also wanted to have the image collection show the top trending pictures and current popular hashtags based on social network so if they wanted to they could use trending information for captions and images

Thank you