opened
fluffy-critter
username_0
## Expected Behavior
<!--- If you're describing a bug, tell us what should happen -->
<!--- If you're suggesting a change/improvement, tell us how it should work -->
<!--- Either way, please set the appropriate labels on the item -->
It would be nice if there were a way to specify different image rendition and set options for an image based on the template that's rendering it. For example, on an image gallery, setting the `count`/`offset` differently on `index` vs. `entry` (without it being global to the template), or having cropping only happen on `index`.

## Possible Solution
<!--- Not obligatory, but suggest a fix/reason for the bug, -->
<!--- or ideas how to implement the addition or change -->

Similar to how there's `fullsize_*` variants of many of the image parameters, maybe there could also be `{template}_*` variants (e.g. `index_crop=(1,2,3,4)`).

Plumbing through the template name would be tricky and issue-prone, though, so maybe it would be better to have the template itself provide e.g. `entry.body(_prefix='index_')`, which would then have e.g. `index_crop` take precedence over `crop`. So then like in `markdown.HtmlRenderer._render_image`, when it computes `composite_args` it can do something like

```python
prefix = composite_args.get('_prefix')
if prefix:
    for k,v in composite_args:
        if k.startswith(prefix):
            composite_args[k[len(prefix):]] = v
```

and do the same when computing `container_args` in `HtmlRenderer.image` or whatever.

## Context
<!--- How has this issue affected you? What are you trying to accomplish? -->
<!--- Providing context helps us come up with a solution that is most useful in the real world -->

Want to do different thumbnail/gallery/etc. layouts for index vs. entry pages on my [art site](https://beesbuzz.biz/art/drawings/), and different cropping for thumbnails vs. detail pages on https://mullinslab.microbiol.washington.edu/people/ just as two simple examples
Some way of specifying different image options for index vs. entry
issue
created
fluffy-critter
username_0
This also needs to support HTML entries. It's probably appropriate to add the necessary functionality to `image.parse_image_spec` which would need to take in the `config` dict.
comment
closed
fluffy-critter
username_0
issue