Не генерируются превью в галерее Minishop2

Помогите, пожалуйста! На хостинге ру-центра не работает генерация превью при загрузке фото в галерею товара.
Появляется следующая ошибка:

[2013-12-06 21:46:50] (ERROR @ /home/staltrub/biletnick.ru/docs/core/model/phpthumb/phpthumb.functions.php: 474) PHP warning: shell_exec() [function.shell-exec]: Unable to execute 'which convert 2>&1'
[2013-12-06 21:46:50] (ERROR @ /assets/components/minishop2/connector.php) Could not generate thumbnail for "/assets/images/products/24/ec9f0156731bc4e49dcef91216d3cf26c7ad1953.jpg". Array
(
[0] => phpThumb() v1.7.9-200712090829 in file «phpthumb.class.php» on line 216
[1] => setCacheDirectory() starting with config_cache_directory = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb/" in file «phpthumb.class.php» on line 919
[2] => setting config_cache_directory to realpath(/home/staltrub/biletnick.ru/docs/core/cache/phpthumb) = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 947
[3] => setSourceFilename(/home/staltrub/biletnick.ru/docs/ms_tgCJIG) set $this->sourceFilename to "/home/staltrub/biletnick.ru/docs/ms_tgCJIG" in file «phpthumb.class.php» on line 243
[4] => file_exists() = 0 in file «phpthumb.class.php» on line 1101
[5] => is_executable() = 0 in file «phpthumb.class.php» on line 1102
[6] => ImageMagickThumbnailToGD() aborting because cannot find convert in $this->config_imagemagick_path (), and `which convert` returned () in file «phpthumb.class.php» on line 1131
[7] => $AvailableImageOutputFormats = array(text;ico;bmp;wbmp;gif;png;jpeg) in file «phpthumb.class.php» on line 884
[8] => $this->thumbnailFormat set to $this->config_output_format «jpeg» in file «phpthumb.class.php» on line 895
[9] => $this->thumbnailFormat set to $this->f «jpeg» in file «phpthumb.class.php» on line 902
[10] => $this->thumbnailQuality set to «90» in file «phpthumb.class.php» on line 912
[11] => $this->sourceFilename set to "/home/staltrub/biletnick.ru/docs/ms_tgCJIG" in file «phpthumb.class.php» on line 813
[12] => setCacheDirectory() starting with config_cache_directory = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 919
[13] => setting config_cache_directory to realpath(/home/staltrub/biletnick.ru/docs/core/cache/phpthumb) = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 947
[14] => SetCacheFilename() _src set from md5($this->sourceFilename) "/home/staltrub/biletnick.ru/docs/ms_tgCJIG" = «c241dd77706b3d351791812de17cfeaa» in file «phpthumb.class.php» on line 3077
[15] => SetCacheFilename() _par set from md5(_bg000000_farC_zc1_h90_w120_dpi150_q90) in file «phpthumb.class.php» on line 3110
[16] => starting ExtractEXIFgetImageSize() in file «phpthumb.class.php» on line 2897
[17] => $this->useRawIMoutput=false because «bg» is set in file «phpthumb.class.php» on line 1226
[18] => $this->useRawIMoutput=false after checking $UnAllowedParameters in file «phpthumb.class.php» on line 1232
[19] => ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file «phpthumb.class.php» on line 1865
[20] => ImageMagickThumbnailToGD() failed in file «phpthumb.class.php» on line 2927
[21] => SetOrientationDependantWidthHeight() starting with «440»x«279» in file «phpthumb.class.php» on line 2876
[22] => SetOrientationDependantWidthHeight() setting w=«120», h=«90» in file «phpthumb.class.php» on line 2892
[23] => exif_thumbnail() does not exist, cannot extract EXIF thumbnail in file «phpthumb.class.php» on line 2974
[24] => starting SourceImageToGD() in file «phpthumb.class.php» on line 3229
[25] => $this->useRawIMoutput=false because «bg» is set in file «phpthumb.class.php» on line 1226
[26] => $this->useRawIMoutput=false after checking $UnAllowedParameters in file «phpthumb.class.php» on line 1232
[27] => ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file «phpthumb.class.php» on line 1865
[28] => Not using EXIF thumbnail data because $this->exif_thumbnail_data is empty in file «phpthumb.class.php» on line 3278
[29] => $this->gdimg_source is still empty in file «phpthumb.class.php» on line 3330
[30] => ImageMagickThumbnailToGD() failed in file «phpthumb.class.php» on line 3332
[31] => phpThumb() v1.7.9-200712090829

All attempts to create GD image source failed.
ImageMagick is not installed (it is highly recommended that you install it).
Source image is too large (440x279 = 0.1Mpx, max=-0.2Mpx) for GD creation (either install ImageMagick or increase PHP memory_limit to at least 11M). in file «phpthumb.class.php» on line 3647
[32] => phpThumb() v1.7.9-200712090829

Image is too large for PHP-GD memory_limit, please install ImageMagick or increase php.ini memory_limit setting in file «phpthumb.class.php» on line 3647
[33] => SourceImageToGD() failed in file «phpthumb.class.php» on line 323
)

[2013-12-06 21:46:50] (ERROR @ /assets/components/minishop2/connector.php) Could not generate thumbnail for "/assets/images/products/24/ec9f0156731bc4e49dcef91216d3cf26c7ad1953.jpg". Array
(
[0] => phpThumb() v1.7.9-200712090829 in file «phpthumb.class.php» on line 216
[1] => setCacheDirectory() starting with config_cache_directory = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb/" in file «phpthumb.class.php» on line 919
[2] => setting config_cache_directory to realpath(/home/staltrub/biletnick.ru/docs/core/cache/phpthumb) = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 947
[3] => setSourceFilename(/home/staltrub/biletnick.ru/docs/ms_bpypW0) set $this->sourceFilename to "/home/staltrub/biletnick.ru/docs/ms_bpypW0" in file «phpthumb.class.php» on line 243
[4] => $AvailableImageOutputFormats = array(text;ico;bmp;wbmp;gif;png;jpeg) in file «phpthumb.class.php» on line 884
[5] => $this->thumbnailFormat set to $this->config_output_format «jpeg» in file «phpthumb.class.php» on line 895
[6] => $this->thumbnailFormat set to $this->f «jpeg» in file «phpthumb.class.php» on line 902
[7] => $this->thumbnailQuality set to «90» in file «phpthumb.class.php» on line 912
[8] => $this->sourceFilename set to "/home/staltrub/biletnick.ru/docs/ms_bpypW0" in file «phpthumb.class.php» on line 813
[9] => setCacheDirectory() starting with config_cache_directory = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 919
[10] => setting config_cache_directory to realpath(/home/staltrub/biletnick.ru/docs/core/cache/phpthumb) = "/home/staltrub/biletnick.ru/docs/core/cache/phpthumb" in file «phpthumb.class.php» on line 947
[11] => SetCacheFilename() _src set from md5($this->sourceFilename) "/home/staltrub/biletnick.ru/docs/ms_bpypW0" = «a987c1209dd42608870d970b7e16505c» in file «phpthumb.class.php» on line 3077
[12] => SetCacheFilename() _par set from md5(_bg000000_farC_zc1_h270_w360_dpi150_q90) in file «phpthumb.class.php» on line 3110
[13] => starting ExtractEXIFgetImageSize() in file «phpthumb.class.php» on line 2897
[14] => $this->useRawIMoutput=false because «bg» is set in file «phpthumb.class.php» on line 1226
[15] => $this->useRawIMoutput=false after checking $UnAllowedParameters in file «phpthumb.class.php» on line 1232
[16] => ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file «phpthumb.class.php» on line 1865
[17] => ImageMagickThumbnailToGD() failed in file «phpthumb.class.php» on line 2927
[18] => SetOrientationDependantWidthHeight() starting with «440»x«279» in file «phpthumb.class.php» on line 2876
[19] => SetOrientationDependantWidthHeight() setting w=«360», h=«270» in file «phpthumb.class.php» on line 2892
[20] => exif_thumbnail() does not exist, cannot extract EXIF thumbnail in file «phpthumb.class.php» on line 2974
[21] => starting SourceImageToGD() in file «phpthumb.class.php» on line 3229
[22] => $this->useRawIMoutput=false because «bg» is set in file «phpthumb.class.php» on line 1226
[23] => $this->useRawIMoutput=false after checking $UnAllowedParameters in file «phpthumb.class.php» on line 1232
[24] => ImageMagickThumbnailToGD() aborting because ImageMagickCommandlineBase() failed in file «phpthumb.class.php» on line 1865
[25] => Not using EXIF thumbnail data because $this->exif_thumbnail_data is empty in file «phpthumb.class.php» on line 3278
[26] => $this->gdimg_source is still empty in file «phpthumb.class.php» on line 3330
[27] => ImageMagickThumbnailToGD() failed in file «phpthumb.class.php» on line 3332
[28] => phpThumb() v1.7.9-200712090829

All attempts to create GD image source failed.
ImageMagick is not installed (it is highly recommended that you install it).
Source image is too large (440x279 = 0.1Mpx, max=-0.2Mpx) for GD creation (either install ImageMagick or increase PHP memory_limit to at least 11M). in file «phpthumb.class.php» on line 3647
[29] => phpThumb() v1.7.9-200712090829

Image is too large for PHP-GD memory_limit, please install ImageMagick or increase php.ini memory_limit setting in file «phpthumb.class.php» on line 3647
[30] => SourceImageToGD() failed in file «phpthumb.class.php» on line 323
)