Derivativeimage, big tmp file and crashing

Hello,
I am using the Derivativeimage plugin to create smaller version of my pictures and I encounter an error (I might have encountered the issue earlier if I had used a classic Omeka install, but I have deactivated the derivate image generation on-the-fly). Now, I have a huge JPG (> 14 000 pixels wide, > 30 Mb) and the temporary file created by imagemagick fills the partition hosting /tmp to 100%, leaving the process unfinished.

For the time being, I have set the has_derivative column to 1 and skipped this specific image but is there a way to limit the tmp space used by imagemagick while generating the derivative files ? I have not found anything in config.ini

Thanks,
Sylvain