There are two save_ functions in ImageMagick.jl which accept AbstractString and Stream.
The Stream version calls getblob and eventually calls MagickSetImageFormat, so we can use Stream(format"XXX",filename) to specify the file format regardless of file extension. The AbstractString version calls writeimage(wand, filename) directly and lets ImageMagick to infer the format.
Thus if we call save(File(format"JPEG","xxx.png"),img), we get a PNG-encoded file (which is not expected).
timholy
commented
4 years ago
There are two save_ functions in ImageMagick.jl which accept
AbstractStringandStream. TheStreamversion callsgetbloband eventually callsMagickSetImageFormat, so we can useStream(format"XXX",filename)to specify the file format regardless of file extension. TheAbstractStringversion callswriteimage(wand, filename)directly and lets ImageMagick to infer the format. Thus if we callsave(File(format"JPEG","xxx.png"),img), we get a PNG-encoded file (which is not expected).