Transparency (alpha) band of PNG images not used when training

A normal image is composed by red, green, and blue (RGB) channels. Some image format, like .png, allow to have 4, where the 4th usually it's the transparency of the image (this is called alpha channel sometimes). In most of our dataset, we exploit this extra channel to put an extra color information, the infrared band (since we use satellite images with 4 bands). When we upload PNG images with 4 bands, and then we download it back from roboflow, this information is lost, as the downloaded images have in the alpha band only 255 as value, and also the RGB values seems slightly modified.

I'm attaching to this email a link to a COCO dataset that can be uploaded to debug this problem: here

Beginne damit, das Problem mit dem verknüpften COCO-Dataset und PNG-Bildern mit vier Bändern zu reproduzieren, und vergleiche die hochgeladenen Bilder mit den heruntergeladenen Ergebnissen. Als abgeschlossen gilt dies, wenn die heruntergeladenen PNGs die Werte der Alpha-/Infrarotbänder beibehalten und die RGB-Kanäle nicht unerwartet verändern.