Transparent Image Overlays in PHP

Hello. I've been working on a few things recently. One thing that has caused me a slight bit of grief is that with php, when I resize an image with transparency to overlay on another image (such as a meme macro or something) I lose the transparency and it turns to black. Therefore, the original image is lost and I have a simple resized overlay with transparency turned into blackness. How do I resize a transparent image in php and keep the transparency? By the way, it's an alpha png.

At times like this, you need to step back and say, "Where's the Balloon Party?"

The image was fixed, but of note, alphablending should have been ON.

At times like this, you need to step back and say, "Where's the Balloon Party?"