Fix picture partial img/source attributes

Remove duplicate src attribute from image tag.
Remove not allowed src attribute from source tag.
Add default sizes attributes to img and source tag.
Fix inconsistent srcset width.

layouts/partials/picture.html

@@ -57,7 +57,7 @@
         <source
           {{ if lt .Width 660 }}
             {{ with .Resize (printf "%dx%d webp" .Width .Height) }}
-              src="{{ .RelPermalink }}"
+              srcset="{{ .RelPermalink }}"
             {{ end }}
           {{ else }}
             srcset=" {{- (.Resize "330x webp").RelPermalink }} 330w,
@@ -70,19 +70,18 @@
               {{ end }}
             {{ end }}
             {{ if gt .Width 1320 }}
-              ,{{ (.Resize "1320x webp").RelPermalink }} 2x
+              ,{{ (.Resize "1320x webp").RelPermalink }} 1320w
             {{ else }}
               {{ with .Resize (printf "%dx%d webp" .Width .Height) }}
                 ,{{ .RelPermalink }} {{ .Width }}w
               {{ end }}
             {{ end }}"
-            src="{{ (.Resize "660x webp").RelPermalink }}"
           {{ end }}
+          sizes="100vw"
           type="image/webp"
         />
       {{ end }}
       <img
-        src="{{ .RelPermalink }}"
         width="{{ $width }}"
         height="{{ $height }}"
         {{ with $class }}class="{{ . }}"{{ end }}
@@ -91,20 +90,20 @@
         {{ if lt .Width 660 }}
           src="{{ .RelPermalink }}"
         {{ else }}
+          src="{{ (.Resize "660x").RelPermalink }}"
           srcset=" {{- (.Resize "330x").RelPermalink }} 330w,
-          {{- (.Resize "660x").RelPermalink }}
-          660w
+          {{- (.Resize "660x").RelPermalink }} 660w
           {{ if gt .Width 1024 }}
             ,{{ (.Resize "1024x").RelPermalink }} 1024w
           {{ else }}
             ,{{ .RelPermalink }} {{ .Width }}w
           {{ end }}
           {{ if gt .Width 1320 }}
-            ,{{ (.Resize "1320x").RelPermalink }} 2x
+            ,{{ (.Resize "1320x").RelPermalink }} 1320w
           {{ else }}
             ,{{ .RelPermalink }} {{ .Width }}w
           {{ end }}"
-          src="{{ (.Resize "660x").RelPermalink }}"
+          sizes="100vw"
         {{ end }}
       />
     </picture>