ffmpeg invalid scale dimension - swScaler

i'm having this issue "swScaler: 6x25 -> 6x25 is invalid scaling dimension Cannot get resampling context" with swScaler while using an ffmpeg command. here is the command and it's output.

# ffmpeg  -i /var/www/site/tmp/cache/bc1a6321b7a595e928be9717edf43027/media.jpg test.bmp
FFmpeg version SVN-r24948, Copyright (c) 2000-2010 the FFmpeg developers
  built on Apr 15 2011 15:10:24 with gcc 4.2.4 (Ubuntu 4.2.4-1ubuntu4)
  configuration: 
  libavutil     50.24. 0 / 50.24. 0
  libavcore      0. 6. 0 /  0. 6. 0
  libavcodec    52.87开发者_StackOverflow. 0 / 52.87. 0
  libavformat   52.78. 3 / 52.78. 3
  libavdevice   52. 2. 1 / 52. 2. 1
  libavfilter    1.38. 1 /  1.38. 1
  libswscale     0.11. 0 /  0.11. 0
Input #0, image2, from '/var/www/site/tmp/cache/bc1a6321b7a595e928be9717edf43027/media.jpg':
  Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
    Stream #0.0: Video: mjpeg, yuvj444p, 6x25 [PAR 72:72 DAR 6:25], 25 tbr, 25 tbn, 25 tbc
swScaler: 6x25 -> 6x25 is invalid scaling dimension
Cannot get resampling context

any help will be appreciated. thanks in advance

FFmpeg is not the right tool for converting images from one format to another. FFmpeg is geared towards videos that frequently have restrictions on their dimensions and won't accept very small input, e.g., 6 by 25.

A much better choice is ImageMagick. The equivalent conversion command would be:

convert input.jpg output.bmp