You cannot fit "LegionOfDragons" in 16 pixels. It will look like a blurry blob.
: Your guild must be at least Level 4 to register a Guild Mark. To register a Union Mark, the guild must be Level 5 . File Format : The image must be a 24-bit Bitmap (.bmp) file. Dimensions : Exactly 16x16 pixels . File Name : For a Guild Mark : Rename the file to guildmark.bmp . For a Union Mark : Rename the file to unionmark.bmp . How to Apply the Emblem Guild Emblem Silkroad 16x16
It had to be a 24-bit BMP file named guildmark.bmp . You cannot fit "LegionOfDragons" in 16 pixels