Halo or jagged edges
A small or compressed source can leave too little detail to recover. Try the original, larger image and inspect against contrasting colors. Avoid judging only against the preview color.
Subject details disappear
White objects on white backgrounds, glass, veils, and fine hair can be hard to distinguish. Choose a source with clearer separation when possible, and review the result before relying on it.
The background looks white
Some viewers display transparent areas on white. Place the image over a colored layer or open it in an editor to confirm the alpha channel. If the output was saved as JPEG, transparency has been flattened.