HTTP-Handler to add watermark and teaser to images

We need an HTTP handler to dynamically add a watermark and teaser to png images. We want to retrieve the modified image using a well-defined URL, e.g.

https://watermark.ourdomain.com/products/<encryptedvalue>.png

The encrypted value is a string like
4RIvn2JdBtXbGVetCLc/VpVBt2d96/yGn/qRQzUEoRAQEWlBXzZ+g1d4UmmymSvOF7xmK/meblsNS4YfT4eRAg==
which contains the parameters for creating the image in an encrypted form:
- Imagename
- Parameter 1
- parameter 2
- Parameter 3
- Parameter 4

Try the encrypted value e.g. on this page:
https://www.online-toolz.com/tools/text-encryption-decryption.php

Image is a .png file. The teaser is an svg template in which certain data must be changed and which is then placed over the image.

See the example image composed of the watermark (easycosmetic), the product image and the teaser created from different parameters.

The handler may be developed with either ASP.NET, php or Phyton.