Picamera does not seem to support TIFF. Here's a list of supported formats from the documentation:
'jpeg' - Write a JPEG file
'png' - Write a PNG file
'gif' - Write a GIF file
'bmp' - Write a Windows bitmap file
'yuv' - Write the raw image data to a file in YUV420 format
'rgb' - Write the raw image data to a file in 24-bit RGB format
'rgba' - Write the raw image data to a file in 32-bit RGBA format
'bgr' - Write the raw image data to a file in 24-bit BGR format
'bgra' - Write the raw image data to a file in 32-bit BGRA format
'raw' - Deprecated option for raw captures; the format is taken from the deprecated raw_format attribute
The "support" for MIME in picamera is limited to automatically stripping the prefix, that is, you could specify the format as jpg
or image/jpg
. Specifying image/tiff
does not automatically makes TIFF supported.