Hello!
this:
<img src="{{'assets/images/footer/EMS_Notre-Dame_Espaces-commun-Batiment.jpg'|theme|resize(800, 600, { filename: true }) }}" alt="plantamour" class="img-fluid">
returns me
<img src="//ndm.test:3000/resize/e21c21b8dbcdbaf4f70e4ec811f97afd-1" alt="plantamour" class="img-fluid">
shouldn’t it be the filename? Am I missing something?
OctoberCMS 3.6.22
After a refresh it should be the correct filename 
You were right. a cache::clear did help.
But I still have a uuid after the name:
<img src="//localhost:3000/storage/app/resources/resize/392_207_0_0_crop/test_b8a8387d8c39ced1400668852dec1caf.jpg" alt="test" class="img-fluid">
Is it possible to have only the name?
Yes, but not yet.
In the next version (v3.7) we will add a group option that will remove the uuid. A unique group should be specified to avoid naming collisions.