Index: openacs-4/packages/xowf/lib/inclass-exam.wf
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowf/lib/inclass-exam.wf,v
diff -u -r1.1.2.17 -r1.1.2.18
--- openacs-4/packages/xowf/lib/inclass-exam.wf	18 Apr 2020 16:16:15 -0000	1.1.2.17
+++ openacs-4/packages/xowf/lib/inclass-exam.wf	18 Apr 2020 16:58:34 -0000	1.1.2.18
@@ -462,8 +462,14 @@
           set files [glob -nocomplain -path $proctoring_dir *.*]
           ns_log notice "proctoring_dir $proctoring_dir files $files"
 
-          set start_date [ns_set get [lindex $revisions 0] creation_date]
-          set end_date [ns_set get [lindex $revisions end] creation_date]
+          if {$revision_id ne ""} {
+            set filtered_revisions [xowf::test_item::answer_manager revisions_up_to $revisions $revision_id]
+          } else {
+            set filtered_revisions $revisions
+          }
+
+          set start_date [ns_set get [lindex $filtered_revisions 0] creation_date]
+          set end_date [ns_set get [lindex $filtered_revisions end] creation_date]
           set start_clock [clock scan [::xo::db::tcl_date $start_date tz_var]]
           set end_clock [clock scan [::xo::db::tcl_date $end_date tz_var]]
           foreach r $revisions {
@@ -481,7 +487,7 @@
                 $start_clock ([expr {$stamp >= $start_clock}]) \
                 && $stamp <= $end_clock ([expr {$stamp <= $end_clock}])"
               if {$inWindow} {
-                dict set image $stamp $type $stamp
+                dict set image $stamp $type $ext
               }
             }
           }
@@ -492,10 +498,12 @@
             append markup {<div style="display: flex">}
             foreach type {camera-image desktop-image} {
               if {[dict exists $image $ts $type]} {
+                set ext [dict get $image $ts $type]
                 append markup [subst {<img src="$img_url&type=$type&ts=$ts&e=$ext">}]
               }
             }
             if {[dict exists $image $ts camera-audio]} {
+              set ext [dict get $image $ts camera-audio]
               append markup [subst {<audio src="$img_url&type=camera-audio&ts=$ts&e=$ext">}]
             }
             append markup </div>\n
@@ -630,7 +638,7 @@
     set proctoring_dir [acs_root_dir]/proctoring/$id/$user_id
     set png_path $proctoring_dir/$type-$ts.$ext
     #ns_log notice "image: $png_path"
-    ns_returnfile 200 image/png $png_path
+    ns_returnfile 200 [ns_guesstype $ts.$ext] $png_path
     ad_script_abort
   }
 
Index: openacs-4/packages/xowf/tcl/test-item-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowf/tcl/test-item-procs.tcl,v
diff -u -r1.7.2.47 -r1.7.2.48
--- openacs-4/packages/xowf/tcl/test-item-procs.tcl	18 Apr 2020 11:35:49 -0000	1.7.2.47
+++ openacs-4/packages/xowf/tcl/test-item-procs.tcl	18 Apr 2020 16:58:34 -0000	1.7.2.48
@@ -1137,6 +1137,7 @@
     #  - marked_results
     #  - answers_panel
     #  - result_table
+    #  - revisions_up_to
     #
 
     :public method create_workflow {
@@ -1335,7 +1336,12 @@
 
     ########################################################################
 
-    :method revisions_up_to {revision_sets revision_id} {
+    :public method revisions_up_to {revision_sets revision_id} {
+      #
+      # Return the revisions of the provided revision set up the
+      # provided revision_id. If this revision_id does not exist,
+      # return the full set.
+      #
       set result ""
       set stop 0
       return [lmap s $revision_sets {