Hey everyone,

I’m currently running into a frustrating image processing roadblock on my self-hosted Zenphoto gallery installation, and I’m hoping someone with more experience with the GD graphics library integration can point me in the right direction.

We are utilizing a private Zenphoto setup to host a massive, organized archive of structural interface layouts, UI concept mockups, and client-side testing screenshots. This gallery is dedicated to cataloging historical visual updates for a specialized [Link removed by administrator due to spam suspicion] workspace utility that our modding community develops and uses to run optimization scripts. Because these screenshots contain custom vectors and specialized interface assets, we require all uploaded items to automatically receive a transparent brand watermark via the core Zenphoto watermark plugin during the server ingestion process.

The primary problem is that whenever a contributor uploads a high-resolution PNG image with a pre-existing alpha transparency layer, the watermark plugin chokes completely. Instead of cleanly overlaying our logo, the processing script outputs a broken image block where the transparent sections are filled with a solid, corrupted black background. Checking our server logs, it looks like Zenphoto's underlying GD graphics library handler is dropping the alpha channel bitmask during the resampling phase, which breaks the image layout completely. If we upload basic JPEGs, the watermark applies flawlessly, but for our technical UI screenshots, crisp PNG quality is mandatory.

Alongside the transparency corruption, we are dealing with a secondary issue regarding category tagging stability. When a bulk upload fails due to this watermark crash, Zenphoto still saves the empty media records into our MySQL database backend. When we try to clean these up by deleting the orphaned entries from the administrative dashboard, the core tagging module freezes entirely, forcing us to manually repair our database tables to get the layout tree working again.

Has anyone else encountered severe alpha channel drops or script crashes when using the watermark extension on transparent PNGs in recent Zenphoto releases, and is there a specific PHP configuration or plugin override we can apply to force the GD handler to preserve image transparency?

While I am pretty sure this post is just "clever" spam - I removed a link as well - since I have no idea what "watermark plugin" or "core tagging module" is referred to, will just link to the user guide article about image problems: https://www.zenphoto.org/news/problems-with-albums-and-images/
Also the general recommendation to try imagick instead of GD.