diff --git a/config/tmux.conf b/config/tmux.conf
index 2852de9..a87e4b9 100644
--- a/config/tmux.conf
+++ b/config/tmux.conf
@@ -67,6 +67,14 @@ if-shell "tmux -V | awk '{print $2}' | awk -F. '{if ($1*1000+$2 >= 3003) exit 0;
 set -as terminal-overrides ',*:Ms=\E]52;c;%p2%s\007'
 set -g set-clipboard external
 
+# iTerm2 supports SIXEL images (since 3.3.0) but doesn't set a distinct TERM
+# to identify itself, so this matches on its usual "xterm-256color" report --
+# any other client reporting that same TERM will also be treated as
+# sixel-capable. Alacritty is deliberately left off: upstream Alacritty has
+# no sixel support, so telling tmux otherwise would replace today's clean
+# text placeholder with garbled escape data.
+set -as terminal-features ",xterm-256color:sixel"
+
 # tmux renamed the copy-mode key table (vi-copy -> copy-mode-vi) and changed
 # bind-key's table flag (-t -> -T) in 2.4. Source the file matching the
 # running tmux so old tmux never parses syntax it doesn't understand.