No input file(s) for generating animation!
Usage:

  img2webp [file_options] [[frame_options] frame_file]... [-o webp_file]

File-level options (only used at the start of compression):
 -min_size ............ minimize size
 -kmax <int> .......... maximum number of frame between key-frames
                        (0=only keyframes)
 -kmin <int> .......... minimum number of frame between key-frames
                        (0=disable key-frames altogether)
 -mixed ............... use mixed lossy/lossless automatic mode
 -near_lossless <int> . use near-lossless image preprocessing
                        (0..100=off), default=100
 -sharp_yuv ........... use sharper (and slower) RGB->YUV conversion
                        (lossy only)
 -loop <int> .......... loop count (default: 0, = infinite loop)
 -v ................... verbose mode
 -h ................... this help
 -version ............. print version number and exit

Per-frame options (only used for subsequent images input):
 -d <int> ............. frame duration in ms (default: 100)
 -lossless ............ use lossless mode (default)
 -lossy ............... use lossy mode
 -q <float> ........... quality
 -m <int> ............. compression method (0=fast, 6=slowest), default=4
 -exact, -noexact ..... preserve or alter RGB values in transparent area
                        (default: -noexact, may cause artifacts
                                  with lossy animations)

example: img2webp -loop 2 in0.png -lossy in1.jpg
                  -d 80 in2.tiff -o out.webp

Note: if a single file name is passed as the argument, the arguments will be
tokenized from this file. The file name must not start with the character '-'.

Supported input formats:
  WebP, JPEG, PNG, PNM (PGM, PPM, PAM)