diff --git a/client/src/docker/docker.bash b/client/src/docker/docker.bash
index f55eb04..0d49e56 100755
--- a/client/src/docker/docker.bash
+++ b/client/src/docker/docker.bash
@@ -92,8 +92,8 @@ function main()
   \e[37;2m# Setup an alias for latest <platform${global_arg_delim_1}user:tag>\e[0m
   $ alias docker-finance=\"$0 archlinux${global_arg_delim_1}${USER}:latest\"
 
-  \e[37;2m# Generate environment and build image\e[0m
-  $ docker-finance gen && docker-finance build
+  \e[37;2m# Generate environment and build default image\e[0m
+  $ docker-finance gen && docker-finance build type=default
 
   \e[37;2m# Bring up container, open shell (type 'exit' to leave)\e[0m
   $ docker-finance up
@@ -124,8 +124,8 @@ function main()
   \e[37;2m# Setup an alias for dev-tools\e[0m
   $ alias docker-finance_dev-tools=\"$0 dev-tools${global_arg_delim_1}${USER}:latest\"
 
-  \e[37;2m# Generate environment and build image\e[0m
-  $ docker-finance_dev-tools gen && docker-finance_dev-tools build
+  \e[37;2m# Generate environment and build default image\e[0m
+  $ docker-finance_dev-tools gen && docker-finance_dev-tools build type=default
 
   \e[37;2m# Spawn a container with given command (removed after command finishes)\e[0m
   $ docker-finance_dev-tools run 'shellcheck --version'
diff --git a/client/src/docker/lib/internal/lib_docker.bash b/client/src/docker/lib/internal/lib_docker.bash
index 683ed42..d232150 100644
--- a/client/src/docker/lib/internal/lib_docker.bash
+++ b/client/src/docker/lib/internal/lib_docker.bash
@@ -46,10 +46,44 @@ if [ -z "$EDITOR" ]; then
   fi
 fi
 
-#
-# `docker compose`
-#
+# Remaining "constructor" implementation
+function lib_docker::__docker()
+{
+  # Docker-related files
+  [ -z "$DOCKER_FINANCE_CLIENT_REPO" ] && lib_utils::die_fatal
+  declare -g global_repo_dockerfiles="${DOCKER_FINANCE_CLIENT_REPO}/client/Dockerfiles/"
 
+  case "$global_platform" in
+    archlinux | ubuntu)
+      global_repo_dockerfiles+="finance"
+      ;;
+    dev-tools)
+      global_repo_dockerfiles+="dev-tools"
+      ;;
+    *)
+      lib_utils::die_fatal "platform was not previously checked"
+      ;;
+  esac
+
+  #
+  # Generate docker-compose.yml
+  #
+
+  [ -z "$global_env_file" ] && lib_utils::die_fatal
+  [ -z "$global_shell_file" ] && lib_utils::die_fatal
+  [ -z "$global_repo_dockerfiles" ] && lib_utils::die_fatal
+
+  local _path="${global_repo_dockerfiles}/docker-compose.yml"
+  lib_utils::print_debug "Generating '${_path}'"
+
+  sed \
+    -e "s|@DOCKER_FINANCE_IMAGE@|${global_image}:${global_tag}|g" \
+    -e "s|@DOCKER_FINANCE_CONTAINER@|${global_container}|g" \
+    -e "s|@DOCKER_FINANCE_NETWORK@|${global_network}|g" \
+    "${_path}.${global_platform}.in" >"$_path" || return $?
+}
+
+# `docker compose` wrapper
 function lib_docker::__docker_compose()
 {
   [ -z "$global_env_file" ] && lib_utils::die_fatal
@@ -66,7 +100,199 @@ function lib_docker::__docker_compose()
 
 function lib_docker::__build()
 {
-  time lib_docker::__docker_compose build --pull docker-finance "$@"
+  [ -z "$global_usage" ] && lib_utils::die_fatal
+  [ -z "$global_arg_delim_1" ] && lib_utils::die_fatal
+  [ -z "$global_arg_delim_2" ] && lib_utils::die_fatal
+  [ -z "$global_arg_delim_3" ] && lib_utils::die_fatal
+
+  [ -z "$global_platform" ] && lib_utils::die_fatal
+
+  case "$global_platform" in
+    archlinux | ubuntu)
+      local -r _usage="
+\e[32mDescription:\e[0m
+
+  Build 'finance' image of given type
+
+\e[32mUsage:\e[0m
+
+  $ $global_usage type${global_arg_delim_2}<type>
+
+\e[32mArguments:\e[0m
+
+  Build type:
+
+    type${global_arg_delim_2}<default|slim|tiny|micro>
+
+\e[32mNotes:\e[0m
+
+  - All builds will continue to incorporate custom Dockerfile (see \`edit help\`)
+  - WARNING: for 'tiny' and 'micro'; use only if you trust pre-compiled assets hosted on GitHub (Microsoft)
+
+\e[32mExamples:\e[0m
+
+  \e[37;2m# Build normal (default) image\e[0m
+  $ $global_usage type${global_arg_delim_2}default
+
+  \e[37;2m# Build a smaller default image but *without* ROOT.cern (meta-analysis) support\e[0m
+  $ $global_usage type${global_arg_delim_2}slim
+
+  \e[37;2m# Build an even smaller default image with *pre-built* hledger-flow binary (but *with* ROOT.cern support)\e[0m
+  $ $global_usage type${global_arg_delim_2}tiny
+
+  \e[37;2m# Build the smallest image possible: the 'tiny' image *without* ROOT.cern support\e[0m
+  $ $global_usage type${global_arg_delim_2}micro
+"
+      ;;
+    dev-tools)
+      local -r _usage="
+\e[32mDescription:\e[0m
+
+  Build 'dev-tools' image of given type
+
+\e[32mUsage:\e[0m
+
+  $ $global_usage type${global_arg_delim_2}<type>
+
+\e[32mArguments:\e[0m
+
+  Build type:
+
+    type${global_arg_delim_2}<default>
+
+\e[32mNotes:\e[0m
+
+  - All builds will continue to incorporate custom Dockerfile (see \`edit help\`)
+
+\e[32mExamples:\e[0m
+
+  \e[37;2m# Build normal (default) image\e[0m
+  $ $global_usage type${global_arg_delim_2}default
+"
+      ;;
+    *)
+      lib_utils::die_fatal "unsupported platform"
+      ;;
+  esac
+
+  #
+  # Ensure supported arguments
+  #
+
+  [ $# -eq 0 ] && lib_utils::die_usage "$_usage"
+
+  for _arg in "$@"; do
+    [[ ! "$_arg" =~ ^type[s]?${global_arg_delim_2} ]] \
+      && lib_utils::die_usage "$_usage"
+  done
+
+  #
+  # Parse arguments before testing
+  #
+
+  # Parse key for value
+  for _arg in "$@"; do
+
+    local _key="${_arg%${global_arg_delim_2}*}"
+    local _len="$((${#_key} + 1))"
+
+    if [[ "$_key" =~ ^type[s]?$ ]]; then
+      local _arg_type="${_arg:${_len}}"
+      [ -z "$_arg_type" ] && lib_utils::die_usage "$_usage"
+    fi
+  done
+
+  #
+  # Test argument values, set globals
+  #
+
+  IFS="$global_arg_delim_3"
+
+  # Arg: type
+  if [ ! -z "$_arg_type" ]; then
+    [[ ! "$_arg_type" =~ ^default$|^slim$|^tiny$|^micro$ ]] \
+      && lib_utils::die_usage "$_usage"
+  fi
+
+  # TODO: factor out parser
+
+  #
+  # Generate Dockerfile
+  #
+
+  [ -z "$DOCKER_FINANCE_UID" ] && lib_utils::die_fatal
+  [ -z "$DOCKER_FINANCE_GID" ] && lib_utils::die_fatal
+  [ -z "$DOCKER_FINANCE_USER" ] && lib_utils::die_fatal
+
+  [ -z "$global_repo_dockerfiles" ] && lib_utils::die_fatal
+
+  local _final="${global_repo_dockerfiles}/Dockerfile"
+  local _in_file="${global_repo_dockerfiles}/Dockerfile.${global_platform}.in"
+
+  lib_utils::print_debug "Generating '${_final}' from '${_in_file}"
+
+  sed \
+    -e "s:@DOCKER_FINANCE_UID@:${DOCKER_FINANCE_UID}:g" \
+    -e "s:@DOCKER_FINANCE_GID@:${DOCKER_FINANCE_GID}:g" \
+    -e "s:@DOCKER_FINANCE_USER@:${DOCKER_FINANCE_USER}:g" \
+    "$_in_file" >"$_final" || return $?
+
+  #
+  # Append to Dockerfile according to type
+  #
+
+  if [[ "$global_platform" == "dev-tools" && "$_arg_type" != "default" ]]; then
+    lib_utils::print_warning "'${_arg_type}' is not supported for 'dev-tools', using 'default'"
+  fi
+
+  if [[ "$global_platform" != "dev-tools" ]]; then
+
+    local _in_files=()
+
+    case "$_arg_type" in
+      default | slim)
+        _in_files+=("hledger-flow.src")
+        [[ "$_arg_type" == "default" ]] && _in_files+=("root")
+        ;;
+      tiny | micro)
+        _in_files+=("hledger-flow.bin")
+        [[ "$_arg_type" == "tiny" ]] && _in_files+=("root")
+        ;;
+      *)
+        lib_utils::die_fatal "unsupported build"
+        ;;
+    esac
+
+    for _file in "${_in_files[@]}"; do
+      local _path="${global_repo_dockerfiles}/${global_platform}/Dockerfile.${_file}.in"
+      lib_utils::print_debug "Appending '${_path}' to '${_final}'"
+      sed \
+        -e "s:@DOCKER_FINANCE_USER@:${DOCKER_FINANCE_USER}:g" \
+        "$_path" >>"$_final" || return $?
+    done
+
+  fi
+
+  #
+  # Append to Dockerfile end-user's custom Dockerfile
+  #
+
+  [ -z "$global_custom_dockerfile" ] && lib_utils::die_fatal
+
+  if [[ ! -f "$global_custom_dockerfile" ]]; then
+    lib_utils::print_debug "'${global_custom_dockerfile}' not found, skipping"
+  else
+    lib_utils::print_debug "Appending '${global_custom_dockerfile}' to '${_final}'"
+    sed \
+      -e "s:@DOCKER_FINANCE_USER@:${DOCKER_FINANCE_USER}:g" \
+      "$global_custom_dockerfile" >>"$_final" || return $?
+  fi
+
+  #
+  # Execute
+  #
+
+  time lib_docker::__docker_compose build --pull docker-finance
 }
 
 function lib_docker::__up()
diff --git a/client/src/docker/lib/lib_docker.bash b/client/src/docker/lib/lib_docker.bash
index 52616bd..ad91bd7 100644
--- a/client/src/docker/lib/lib_docker.bash
+++ b/client/src/docker/lib/lib_docker.bash
@@ -109,69 +109,8 @@ function lib_docker::docker()
   # Setup remaining client/container globals
   lib_gen::gen || return $?
 
-  # TODO: all following docker related should be internal
-
-  # Docker-related files
-  [ -z "$global_repo_client" ] && lib_utils::die_fatal
-  declare -g global_repo_dockerfiles="${global_repo_client}/Dockerfiles/"
-
-  case "$global_platform" in
-    archlinux | ubuntu)
-      global_repo_dockerfiles+="finance"
-      ;;
-    dev-tools)
-      global_repo_dockerfiles+="dev-tools"
-      ;;
-    *)
-      lib_utils::die_fatal "platform was not previously checked"
-      ;;
-  esac
-
-  #
-  # docker-compose
-  #
-
-  [ -z "$global_env_file" ] && lib_utils::die_fatal
-  [ -z "$global_shell_file" ] && lib_utils::die_fatal
-
-  local _path="${global_repo_dockerfiles}/docker-compose.yml"
-  lib_utils::print_debug "Generating '${_path}'"
-
-  sed \
-    -e "s|@DOCKER_FINANCE_IMAGE@|${global_image}:${global_tag}|g" \
-    -e "s|@DOCKER_FINANCE_CONTAINER@|${global_container}|g" \
-    -e "s|@DOCKER_FINANCE_NETWORK@|${global_network}|g" \
-    "${_path}.${global_platform}.in" >"$_path" || return $?
-
-  #
-  # Dockerfile
-  #
-
-  [ -z "$DOCKER_FINANCE_UID" ] && lib_utils::die_fatal
-  [ -z "$DOCKER_FINANCE_GID" ] && lib_utils::die_fatal
-  [ -z "$DOCKER_FINANCE_USER" ] && lib_utils::die_fatal
-
-  local _path="${global_repo_dockerfiles}/Dockerfile"
-  lib_utils::print_debug "Generating '${_path}'"
-
-  sed \
-    -e "s:@DOCKER_FINANCE_UID@:${DOCKER_FINANCE_UID}:g" \
-    -e "s:@DOCKER_FINANCE_GID@:${DOCKER_FINANCE_GID}:g" \
-    -e "s:@DOCKER_FINANCE_USER@:${DOCKER_FINANCE_USER}:g" \
-    "${_path}.${global_platform}.in" >"$_path" || return $?
-
-  # Append end-user's custom Dockerfile to final Dockerfile
-  [ -z "$global_custom_dockerfile" ] && lib_utils::die_fatal
-
-  if [[ ! -f "$global_custom_dockerfile" ]]; then
-    lib_utils::print_debug "'${global_custom_dockerfile}' not found, skipping"
-    return 0
-  fi
-
-  lib_utils::print_debug "Appending '${global_custom_dockerfile}' to '${_path}'"
-  sed \
-    -e "s:@DOCKER_FINANCE_USER@:${DOCKER_FINANCE_USER}:g" \
-    "$global_custom_dockerfile" >>"$_path" || return $?
+  # Remaining "constructor" implementation
+  lib_docker::__docker || return $?
 
   return 0
 }