To preserve image transparency in Pixlr, which file format should you save the file in?

Saving an image in the PNG file format is the best choice for preserving image transparency. PNG, which stands for Portable Network Graphics, supports transparency through an alpha channel, allowing for varying degrees of transparency for individual pixels. This feature is especially useful when images are layered or when you want to overlay graphics without a solid background.

In contrast, other file formats do not support transparency in the same way. JPEG files, for example, are widely used for photographs but do not support any transparency at all; instead, they fill transparent areas with a solid color. BMP (Bitmap) files can support transparency, but the format is not commonly used for web graphics due to larger file sizes and lack of compression. TIF (Tagged Image File Format) can also support transparency, but it is generally more suited for high-quality print graphics and does not have the same level of support across web applications as PNG does. Thus, for preserving image transparency effectively, PNG is the ideal format to choose.