diff --git a/project.clj b/project.clj
index b753cd1..3898e1c 100644
--- a/project.clj
+++ b/project.clj
@@ -27,6 +27,7 @@
                  [org.clojure/core.memoize "0.5.9"]
                  [org.clojure/data.json "0.2.6"]
                  [org.clojure/tools.logging "0.4.0"]
+                 [org.clojure/tools.trace "0.7.10"]
                  [org.slf4j/slf4j-api "1.7.25"]
                  [org.slf4j/log4j-over-slf4j "1.7.25"]
                  [org.slf4j/jul-to-slf4j "1.7.25"]
diff --git a/resources/config.edn b/resources/config.edn
index 059dfeb..6ff0faf 100644
--- a/resources/config.edn
+++ b/resources/config.edn
@@ -32,11 +32,12 @@
   :default-locale       "en-GB"         ;; default language used for messages
   :formatters                           ;; formatters for processing markdown
                                         ;; extensions.
-                        {"vega"         smeagol.formatting/process-vega
-                         "vis"          smeagol.formatting/process-vega
-                         "mermaid"      smeagol.extensions.mermaid/process-mermaid
-                         "backticks"    smeagol.formatting/process-backticks
-                         "pswp"         smeagol.extensions.photoswipe/process-photoswipe}
+  {:vega         {:formatter "smeagol.extensions.vega/process-vega" }
+   :vis          {:formatter "smeagol.extensions.vega/process-vega" }
+   :mermaid      {:formatter "smeagol.extensions.mermaid/process-mermaid" }
+   :backticks    {:formatter "smeagol.formatting/process-backticks" }
+   :pswp         {:formatter "smeagol.extensions.photoswipe/process-photoswipe" }
+   }
   :log-level            :info           ;; the minimum logging level; one of
                                         ;; :trace :debug :info :warn :error :fatal
   :js-from              :cdnjs          ;; where to load JavaScript libraries
diff --git a/resources/public/content/Simplified example gallery.md b/resources/public/content/Simplified example gallery.md
index 4cff2da..eac0394 100644
--- a/resources/public/content/Simplified example gallery.md	
+++ b/resources/public/content/Simplified example gallery.md	
@@ -13,7 +13,7 @@ That's all there is to it - a sequence of image links just as you'd write them a
 
 ## The Gallery
 
-This page holds another example Photoswipe gallery, this time using a simpler, Markdown-based specification. Processing this specification takes more work than the full syntax used in the other [Example gallery], so the gallery may be slower to load; but it's much easier to configure.
+This page holds another example Photoswipe gallery, this time using a simpler, Markdown-based specification. Processing this specification takes more work than the full syntax used in the other [[Example gallery]], so the gallery may be slower to load; but it's much easier to configure.
 
 ```pswp
 ![Frost on a gate, Laurieston](content/uploads/g1.jpg)
diff --git a/src/smeagol/extensions/photoswipe.clj b/src/smeagol/extensions/photoswipe.clj
index 31c6e42..2df235e 100644
--- a/src/smeagol/extensions/photoswipe.clj
+++ b/src/smeagol/extensions/photoswipe.clj
@@ -174,10 +174,15 @@
 ;;   1)
 
 (defn process-photoswipe
-    [^String url-or-pswp-spec ^Integer index]
+  [^String url-or-pswp-spec ^Integer index]
+  (log/info "process-photoswipe called with arg1 `"
+            url-or-pswp-spec "`; arg2 `" index "`.")
   (let [data (resource-url-or-data->data url-or-pswp-spec)
-        spec (cs/trim (:data data))]
-    (if
-      (cs/starts-with? spec "![")
-      (process-simple-photoswipe spec index)
-      (process-full-photoswipe spec index))))
+        spec (cs/trim (:data data))
+        result
+        (if
+          (cs/starts-with? spec "![")
+          (process-simple-photoswipe spec index)
+          (process-full-photoswipe spec index))]
+    (log/info "process-photoswipe returning `" result "`.")
+    ))
diff --git a/src/smeagol/formatting.clj b/src/smeagol/formatting.clj
index fa4f2f6..87d8f45 100644
--- a/src/smeagol/formatting.clj
+++ b/src/smeagol/formatting.clj
@@ -8,7 +8,8 @@
             [markdown.core :as md]
             [smeagol.configuration :refer [config]]
             [smeagol.extensions.mermaid :refer [process-mermaid]]
-            [smeagol.extensions.photoswipe :refer [process-photoswipe]]))
+            [smeagol.extensions.photoswipe :refer [process-photoswipe]]
+            [taoensso.timbre :as log]))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;
@@ -149,7 +150,17 @@
          ;; I need to put the backticks back in.
          remarked (if (odd? index) (str "```" fragment "\n```") fragment)
          first-token (get-first-token fragment)
-         formatter (eval ((:formatters config) first-token))]
+         formatter (if-not
+                     (empty? first-token)
+                     (try
+                       (let [kw (keyword first-token)]
+                         (read-string (-> config :formatters kw :formatter)))
+                       (catch Exception _
+                         (do
+                           (log/info "No formatter found for extension `" first-token "`")
+                           ;; no extension registered - there sometimes won't be,
+                           ;; and it doesn't matter
+                           nil))))]
      (cond
        (empty? fragments)
        (assoc result :text