the problem: one of my images got out of sync with my server. so, i didn't really has the image on my var folder, but the image was present on the DB. now, i get this big twig_error_runtime:

Impossible to access an attribute ( "uri" ) on a NULL variable ( "" ) in EzPublishCoreBundle::content_fields.html.twig at line 416

this is how i render the image:
{{ ez_render_field(content, 'image', {'parameters': { 'alias': 'link' }}) }}

Note: This issue will only be reproduced as described on 5.3, not on master due to changes in Image alias generation.
For master, another issue is present: EZP-23534