Merge pull request #80 from opds-community/image-requirement

Changed requirements for images in OPDS 2.0

opds-2.0.md

@@ -146,7 +146,7 @@ Publications <em class="rfc">must</em> either be:
 - a [Readium Web Publication](https://github.com/readium/webpub-manifest) with no restrictions in terms of access (no payment, no credentials required, no limitations whatsoever)
 - or an [OPDS Publication](#51-opds-publication)   
 
-Each publication listed in an OPDS feed <em class="rfc">must</em> contain an `images` collection.
+Each publication listed in an OPDS feed <em class="rfc">should</em> contain an `images` collection.
 
 **Example**
 
@@ -192,7 +192,7 @@ An `images` collection is meant to support responsive images across all types of
 
 Link Objects in `images` <em class="rfc">may</em> include any number of image format, resolution or aspect ratio.
 
-At least one image resource <em class="rfc">must</em> use one of the following formats: `image/jpeg`, `image/png` or `image/gif`.
+At least one image resource <em class="rfc">must</em> use one of the following formats: `image/jpeg`, `image/avif`, `image/png` or `image/gif`.
 
 **Example**
 

schema/publication.schema.json

@@ -58,12 +58,13 @@
       "minItems": 1,
       "allOf": [
         {
-          "description": "At least one image resource must use one of the following formats: image/jpeg, image/png or image/gif.",
+          "description": "At least one image resource must use one of the following formats: image/jpeg, image/avif, image/png or image/gif.",
           "contains": {
             "properties": {
               "type": {
                 "enum": [
                   "image/jpeg",
+                  "image/avif",
                   "image/png",
                   "image/gif"
                 ]
@@ -76,7 +77,6 @@
   },
   "required": [
     "metadata",
-    "links",
-    "images"
+    "links"
   ]
 }