Thumbnail generation unsuccessful

• DEBUG post_id=5757
• DEBUG Found YAPB image
• DEBUG w=160
• DEBUG q=70
• DEBUG fltr[]=usm|60|0.5|3
• ERROR phpThumb couldn't generate thumbnail.
• INFO Writing out phpThumb internal debug messages:
• DEBUG phpThumb: phpThumb() v1.7.8-200709161750 in file "phpthumb.class.php" on line 216
• DEBUG phpThumb: setSourceFilename(/wp-content/uploads/zacksnydersm.jpg) set $this->sourceFilename to "/wp-content/uploads/zacksnydersm.jpg" in file "phpthumb.class.php" on line 243
• DEBUG phpThumb: file_exists() = 0 in file "phpthumb.class.php" on line 1099
• DEBUG phpThumb: is_executable() = 0 in file "phpthumb.class.php" on line 1100
• DEBUG phpThumb: ImageMagickThumbnailToGD() aborting because cannot find convert in $this->config_imagemagick_path (), and `which convert` returned (which: no convert in (/sbin:/usr/sbin:/bin:/usr/bin)) in file "phpthumb.class.php" on line 1129
• DEBUG phpThumb: $AvailableImageOutputFormats = array(text;ico;bmp;wbmp;gif;png;jpeg) in file "phpthumb.class.php" on line 882
• DEBUG phpThumb: $this->thumbnailFormat set to $this->config_output_format "jpeg" in file "phpthumb.class.php" on line 893
• DEBUG phpThumb: $this->thumbnailQuality set to "70" in file "phpthumb.class.php" on line 910
• DEBUG phpThumb: ResolveFilenameToAbsolute() prepending $this->config_document_root (/var/www/html) to $filename (/wp-content/uploads/zacksnydersm.jpg) resulting in ($AbsoluteFilename = "/var/www/html/wp-content/uploads/zacksnydersm.jpg") in file "phpthumb.class.php" on line 1023
• DEBUG phpThumb: $this->sourceFilename set to "/var/www/html/wp-content/uploads/zacksnydersm.jpg" in file "phpthumb.class.php" on line 811
• DEBUG phpThumb: phpThumb() v1.7.8-200709161750 "/var/www/html/wp-content/uploads/zacksnydersm.jpg" does not exist in file "phpthumb.class.php" on line 3614
• DEBUG phpThumb: setCacheDirectory() starting with config_cache_directory = "" in file "phpthumb.class.php" on line 917
• DEBUG phpThumb: $this->config_cache_directory () is not a directory in file "phpthumb.class.php" on line 953
• DEBUG phpThumb: SetCacheFilename() failed because $this->config_cache_directory is empty in file "phpthumb.class.php" on line 2999
• DEBUG phpThumb: starting ExtractEXIFgetImageSize() in file "phpthumb.class.php" on line 2856
• DEBUG phpThumb: GetImageSize("/var/www/html/wp-content/uploads/zacksnydersm.jpg") failed in file "phpthumb.class.php" on line 2879
• DEBUG phpThumb: $this->useRawIMoutput=true after checking $UnAllowedParameters in file "phpthumb.class.php" on line 1223
• DEBUG phpThumb: ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file "phpthumb.class.php" on line 1827
• DEBUG phpThumb: ImageMagickThumbnailToGD() failed in file "phpthumb.class.php" on line 2886
• DEBUG phpThumb: SetOrientationDependantWidthHeight() starting with ""x"" in file "phpthumb.class.php" on line 2835
• DEBUG phpThumb: SetOrientationDependantWidthHeight() setting w="160", h="0" in file "phpthumb.class.php" on line 2851
• DEBUG phpThumb: EXIF thumbnail extraction: (size=0; type=""; 0x0) in file "phpthumb.class.php" on line 2938
• DEBUG phpThumb: starting SourceImageToGD() in file "phpthumb.class.php" on line 3196
• DEBUG phpThumb: $this->useRawIMoutput=true after checking $UnAllowedParameters in file "phpthumb.class.php" on line 1223
• DEBUG phpThumb: ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file "phpthumb.class.php" on line 1827
• DEBUG phpThumb: starting ImageCreateFromFilename(/var/www/html/wp-content/uploads/zacksnydersm.jpg) in file "phpthumb.class.php" on line 3111
• DEBUG phpThumb: empty $filename or GetImageSize(/var/www/html/wp-content/uploads/zacksnydersm.jpg) failed in file "phpthumb.class.php" on line 3160
• DEBUG phpThumb: Populating $rawimagedata in file "phpthumb.class.php" on line 3168
• DEBUG phpThumb: cannot fopen(/var/www/html/wp-content/uploads/zacksnydersm.jpg) in file "phpthumb.class.php" on line 3179
• DEBUG phpThumb: Not using EXIF thumbnail data because $this->exif_thumbnail_data is empty in file "phpthumb.class.php" on line 3245
• DEBUG phpThumb: $this->gdimg_source is still empty in file "phpthumb.class.php" on line 3297
• DEBUG phpThumb: ImageMagickThumbnailToGD() failed in file "phpthumb.class.php" on line 3299
• DEBUG phpThumb: phpThumb() v1.7.8-200709161750 Unknown image type identified by "" () in SourceImageToGD()[3411] in file "phpthumb.class.php" on line 3614
• DEBUG phpThumb: SourceImageToGD() failed in file "phpthumb.class.php" on line 323