diff --git a/gtoolkit/run.sh b/gtoolkit/run.sh
index 76eaebdb..5bf195c0 100644
--- a/gtoolkit/run.sh
+++ b/gtoolkit/run.sh
@@ -111,7 +111,14 @@ gtoolkit::prepare_gt() {
   download_name="$(basename "${gtoolkit_image_url}")"
   target="${SMALLTALK_CI_CACHE}/${download_name}"
 
-  if ! is_file "${target}"; then
+  if "${config_update_image}" && is_dir "${target}"; then
+    print_info "Removing cached image resources for ${smalltalk_name} (update forced)"
+    rm -r "${target}"
+  fi
+  if ! is_dir "${target}"; then
+    mkdir "${target}"
+  fi
+  if ! is_file "${target}"/*.image; then
     fold_start download_image "Downloading ${smalltalk_name} image..."
       download_file "${gtoolkit_image_url}" "${target}"
     fold_end download_image
diff --git a/pharo/run.sh b/pharo/run.sh
index cab26ffe..bf34e524 100644
--- a/pharo/run.sh
+++ b/pharo/run.sh
@@ -278,14 +278,20 @@ pharo::prepare_image() {
   local target="${SMALLTALK_CI_CACHE}/${smalltalk_name}"
   local pharo_zeroconf="${target}/zeroconfig"
 
+  if "${config_update_image}" && is_dir "${target}"; then
+    print_info "Removing cached image resources for ${smalltalk_name} (update forced)"
+    rm -r "${target}"
+  fi
   if ! is_dir "${target}"; then
     mkdir "${target}"
-    pushd "${target}" > /dev/null
+  fi
+  if ! is_file "${target}"/*.image; then
+    pushd "${target}" >/dev/null
     fold_start download_image "Downloading ${smalltalk_name} image..."
       download_file "${pharo_image_url}" "${pharo_zeroconf}"
       retry 3 "bash ${pharo_zeroconf}"
     fold_end download_image
-    popd > /dev/null
+    popd >/dev/null
   fi
 
   print_info "Preparing Pharo image..."
diff --git a/run.sh b/run.sh
index 0da83a30..32062793 100755
--- a/run.sh
+++ b/run.sh
@@ -280,6 +280,21 @@ validate_configuration() {
   fi
 }
 
+################################################################################
+# Set options that depend on the contex, i.e., the input values and selections
+# performed so far.
+################################################################################
+set_context_options() {
+  case "${config_smalltalk}" in
+    *-alpha | *-trunk)
+      print_info "Forcing image update for in-development version"
+      config_update_image="true"
+      ;;
+    *)
+      ;;
+  esac
+}
+
 ################################################################################
 # Handle user-defined options.
 # Locals:
@@ -287,6 +302,7 @@ validate_configuration() {
 #   config_debug
 #   config_headless
 #   config_smalltalk
+#   config_update_image
 #   config_verbose
 # Arguments:
 #   All positional parameters
@@ -344,6 +360,10 @@ parse_options() {
       fi
       shift 2
       ;;
+    -u | --update-image)
+      config_update_image="true"
+      shift
+      ;;
     -v | --verbose)
       config_verbose="true"
       shift
@@ -529,10 +549,11 @@ main() {
   local config_clean="false"
   local config_debug="false"
   local config_first_arg_or_empty=""
-  local config_headless="true"
+  export config_headless="true"
   local config_image=""
   local config_colorful="true"
   export config_tracking="true"
+  export config_update_image="false"
   local config_verbose="false"
   local config_vm=""
   local config_vm_dir
@@ -544,6 +565,7 @@ main() {
   ensure_ston_config_exists "${config_first_arg_or_empty}"
   select_smalltalk
   validate_configuration
+  set_context_options
   config_vm_dir="${SMALLTALK_CI_VMS}/${config_smalltalk}"
   prepare_folders
   export_coveralls_data
diff --git a/squeak/run.sh b/squeak/run.sh
index 758eba42..4061150f 100755
--- a/squeak/run.sh
+++ b/squeak/run.sh
@@ -74,6 +74,10 @@ squeak::download_prepared_image() {
   local git_tag=$2
   local target="${SMALLTALK_CI_CACHE}/${download_name}"
 
+  if "${config_update_image}" && is_file "${target}"; then
+    print_info "Removing cached image resources for ${smalltalk_name} (update forced)"
+    rm "${target}"
+  fi
   if ! is_file "${target}"; then
     fold_start download_image "Downloading '${download_name}' testing image..."
       download_file "${BASE_DOWNLOAD}/${git_tag}/${download_name}" "${target}"