Images error 500

[hounded]

New to sylius the following error I can't get past, if I can't get images working I'm considering oscar

An example url
http://localhost:8000/app_dev.php/media/cache/resolve/sylius_shop_product_thumbnail/cb/94/d924f0a0093e349d5d697a728431.jpeg

500 Internal Server Error

Any ideas or pointers to why the images are not loading, following the URL gives

Unable to create image for path "a7/d9/b19a5df25abd2eebdafa2f1a0560.jpeg" and filter "sylius_shop_product_large_thumbnail". Message was "Unable to open image /var/www/sylius/web/media/image/a7/d9/b19a5df25abd2eebdafa2f1a0560.jpeg"

Do I need to set some liip settings in config?

[ben-joostens]

It seems that PHP installs GD without jpeg support (add VarDumper::dump(gd_info()); to your app_dev.php to see whether it did).

I basically added this to the Dockerfile:

RUN docker-php-ext-configure gd \
    --with-freetype-dir=/usr/include/ \
    --with-jpeg-dir=/usr/include/ \
    --with-xpm-dir=/usr/include \
    --with-webp-dir=/usr/include/ # php >=7.0 (use libvpx for php <7.0)
RUN docker-php-ext-install gd

Blatantly stolen from https://github.com/exozet/docker-php-fpm/blob/master/7.1/Dockerfile, as it took a bit of fiddling. With some variations of the above, GD wasn't installed at all.