Glide preset issue

Started with Glide preset, following along Jacks screencast. Seems that preset on glide doesn’t work for me…

{{ assets container="img" }}
    <img src="{{ glide:url height="200" width="200" blur="25" }}">
  {{ /assets }}

results are OK, but

{{ assets container="img" }}
    <img src="{{ glide:url preset="thumbnail" }}">
  {{ /assets }}

results in just the image, no manipulations

my assets.yaml:

image_manipulation_route: /img
image_manipulation_secure: true
auto_crop: true
image_manipulation_driver: gd
image_manipulation_cached: false
image_manipulation_presets:
  thumbnail:
    w: 200
    h: 200
    blur: 25
thumbnail_max_width: 6000
thumbnail_max_height: 6000

pretty standard stuff in there