Automate a web task we do daily!

General information for the business: We sell clothes
Kind of development: New program from scratch
Description of requirements/functionality: We upload products to a popular website daily. We do not own the website, we are just a seller on the website. We upload about 100 products a day, but this can be quite time consuming. I am not sure if this is possible, but we are looking to see if someone can develop some sort of way, that we can make a spreadsheet, and store all of our images in a certain folder and it can automatically upload our products for us, including all data fields etc, and post the products. If we could do this about 8 time a day, for 10 products each time.

I have no idea how this would work, or if it is even possible. But it would be greta if we could automate this aspect of our business, it would free up an employee for the full day, and allow us to upload out of business hours.

I am open to ideas of how this would work etc. The website allows me to upload products on a dedicated list product page very similar to eBay and is all based on the site. there is no backend, or anything technical to the site, it is all on aeasy to use user interface.

if you have any questions please ask.

The budget is an estimate and open to offers if anyone thinks this is possible and understand the job description and a way around this.
Extra notes: