#converting large files with ImageMagick
#get a large image
wget "https://upload.wikimedia.org/wikipedia/commons/f/f8/Fulmer_Falls_Closeup_3000px.jpg" -O 1.jpg

#make it many images
for i in `seq 1 200`;do cp 1.jpg $i.jpg;done

#Convert to PDF and get an error
convert *.jpg 1.pdf

#up your cache limits for ImageMagick
sudo vim /etc/ImageMagick-6/policy.xml
#memory to 3GiB
#Disk to 8GiB

#also change temporary-path to save SSD