Add image-only spam detection and tracking

Add support for detecting and tracking image-only spam across channels. spamDetector.js: introduce image helpers (isImageAttachment, getImageAttachments), buildImageFingerprint, isImageOnlyMessage, and extend detectSpam to report image-only reasons and a duplicateImageAcrossChannels flag. rapidSpamTracker.js: refactor cross-channel tracking with trackCrossChannelPost, pruneExpiredPosts, dedupePriorMessages, and add trackImageOnlySpam which uses optional image fingerprints; export dedupePriorMessages. index.js: wire image-only tracking into message handling (build fingerprint, trackImageOnlySpam, pass duplicateImageAcrossChannels to detectSpam), merge and dedupe prior message lists, and include attachments in mod log previews. commands.js: update detection rules text to mention image spam. These changes enable identifying image-only spam (including fingerprinting) and avoid duplicate prior-message entries when creating moderation logs.

Anti-Spam/src/commands.js

@@ -141,10 +141,8 @@ export async function handleAntispamCommand(interaction) {
         {
           name: "Detection rules",
           value: [
-            "Same message in multiple channels",
+            "Text spam: same message in multiple channels + role ping + link (all three)",
-            "Any role ping (or @everyone/@here)",
+            "Image spam: image-only message posted across multiple channels",
-            "Contains a link",
-            "(all three required)",
           ].join("\n"),
         },
         {

Anti-Spam/src/index.js

@@ -6,8 +6,13 @@ import {
   EmbedBuilder,
 } from "discord.js";
 import { config } from "./config.js";
-import { collectScannableText, detectSpam } from "./spamDetector.js";
+import {
-import { trackCrossChannelMessage } from "./rapidSpamTracker.js";
+  buildImageFingerprint,
+  collectScannableText,
+  detectSpam,
+  isImageOnlyMessage,
+} from "./spamDetector.js";
+import { trackCrossChannelMessage, trackImageOnlySpam, dedupePriorMessages } from "./rapidSpamTracker.js";
 import { getGuildSettings } from "./guildSettings.js";
 import { handleAntispamCommand } from "./commands.js";
 import { registerCommands, registerCommandsForGuild } from "./registerCommands.js";
@@ -138,6 +143,15 @@ async function handleSpam(message, detection, guildSettings, priorMessages = [])
       name: "Message preview",
       value: preview || "(empty)",
     });
+  } else if (message.attachments.size > 0) {
+    const attachmentPreview = [...message.attachments.values()]
+      .slice(0, 3)
+      .map((attachment) => attachment.name || attachment.url)
+      .join("\n");
+    embed.addFields({
+      name: "Attachments",
+      value: attachmentPreview || "(none)",
+    });
   }
 
   await sendModLog(guild, guildSettings, embed);
@@ -227,13 +241,30 @@ client.on("messageCreate", async (message) => {
     scannableText
   );
 
+  let imageCrossChannel = { duplicateAcrossChannels: false, priorMessages: [] };
+  if (isImageOnlyMessage(message)) {
+    imageCrossChannel = trackImageOnlySpam(
+      message.guild.id,
+      message.author.id,
+      message.channel.id,
+      message.id,
+      buildImageFingerprint(message)
+    );
+  }
+
   const detection = detectSpam(message, {
     duplicateAcrossChannels: crossChannel.duplicateAcrossChannels,
+    duplicateImageAcrossChannels: imageCrossChannel.duplicateAcrossChannels,
   });
 
   if (!detection.isSpam) return;
 
-  await handleSpam(message, detection, guildSettings, crossChannel.priorMessages);
+  const priorMessages = dedupePriorMessages([
+    ...crossChannel.priorMessages,
+    ...imageCrossChannel.priorMessages,
+  ]);
+
+  await handleSpam(message, detection, guildSettings, priorMessages);
 });
 
 process.on("unhandledRejection", (error) => {

Anti-Spam/src/rapidSpamTracker.js

@@ -5,8 +5,18 @@ function normalizeKey(text) {
   return text.toLowerCase().replace(/\s+/g, " ").trim().slice(0, 200);
 }
 
-export function trackCrossChannelMessage(guildId, userId, channelId, messageId, text) {
+function dedupePriorMessages(priorMessages) {
-  const normalized = normalizeKey(text);
+  const seen = new Set();
+  return priorMessages.filter(({ channelId, messageId }) => {
+    const entry = `${channelId}:${messageId}`;
+    if (seen.has(entry)) return false;
+    seen.add(entry);
+    return true;
+  });
+}
+
+function trackCrossChannelPost(guildId, userId, channelId, messageId, keySuffix) {
+  const normalized = normalizeKey(keySuffix);
   if (!normalized) {
     return { duplicateAcrossChannels: false, priorMessages: [] };
   }
@@ -34,7 +44,14 @@ export function trackCrossChannelMessage(guildId, userId, channelId, messageId,
     firstSeen: now,
   });
 
-  if (recentPosts.size > 5000) {
+  pruneExpiredPosts(now);
+
+  return { duplicateAcrossChannels: false, priorMessages: [] };
+}
+
+function pruneExpiredPosts(now) {
+  if (recentPosts.size <= 5000) return;
+
   for (const [entryKey, entry] of recentPosts) {
     if (now - entry.firstSeen > WINDOW_MS) {
       recentPosts.delete(entryKey);
@@ -42,5 +59,25 @@ export function trackCrossChannelMessage(guildId, userId, channelId, messageId,
   }
 }
 
-  return { duplicateAcrossChannels: false, priorMessages: [] };
+export function trackCrossChannelMessage(guildId, userId, channelId, messageId, text) {
+  return trackCrossChannelPost(guildId, userId, channelId, messageId, normalizeKey(text));
 }
+
+export function trackImageOnlySpam(guildId, userId, channelId, messageId, fingerprint) {
+  const trackers = [trackCrossChannelPost(guildId, userId, channelId, messageId, "imgonly")];
+
+  if (fingerprint) {
+    trackers.push(
+      trackCrossChannelPost(guildId, userId, channelId, messageId, `imgfp:${fingerprint}`)
+    );
+  }
+
+  const duplicateAcrossChannels = trackers.some((tracker) => tracker.duplicateAcrossChannels);
+  const priorMessages = duplicateAcrossChannels
+    ? dedupePriorMessages(trackers.flatMap((tracker) => tracker.priorMessages))
+    : [];
+
+  return { duplicateAcrossChannels, priorMessages };
+}
+
+export { dedupePriorMessages };

Anti-Spam/src/spamDetector.js

@@ -61,12 +61,61 @@ function hasRolePing(message) {
   return ROLE_MENTION_TEST.test(message.content ?? "");
 }
 
-export function detectSpam(message, { duplicateAcrossChannels = false } = {}) {
+function isImageAttachment(attachment) {
+  if (attachment.contentType?.startsWith("image/")) return true;
+  return Boolean(attachment.width && attachment.height);
+}
+
+export function getImageAttachments(message) {
+  return [...(message.attachments?.values() ?? [])].filter(isImageAttachment);
+}
+
+export function buildImageFingerprint(message) {
+  const images = getImageAttachments(message);
+  const stickers = [...(message.stickers?.values() ?? [])].map((sticker) => sticker.id);
+
+  const imageParts = images
+    .map(
+      (attachment) =>
+        `${(attachment.name ?? "").toLowerCase()}:${attachment.size}:${attachment.width ?? 0}x${attachment.height ?? 0}`
+    )
+    .sort();
+
+  const stickerPart = stickers.length > 0 ? `stickers:${stickers.sort().join(",")}` : "";
+
+  const fingerprint = [imageParts.join("|"), stickerPart].filter(Boolean).join("|");
+  return fingerprint || null;
+}
+
+export function isImageOnlyMessage(message) {
+  const content = (message.content ?? "").trim();
+  if (content) return false;
+  if (hasRolePing(message)) return false;
+
+  const images = getImageAttachments(message);
+  const stickers = message.stickers?.size ?? 0;
+  if (images.length === 0 && stickers === 0) return false;
+
+  const attachments = [...(message.attachments?.values() ?? [])];
+  if (attachments.length > images.length) return false;
+
+  for (const embed of message.embeds ?? []) {
+    if (embed.title || embed.description || embed.url) return false;
+  }
+
+  return true;
+}
+
+export function detectSpam(
+  message,
+  { duplicateAcrossChannels = false, duplicateImageAcrossChannels = false } = {}
+) {
   const scannableText = collectScannableText(message);
   const urls = extractUrls(scannableText);
   const hasLink = urls.length > 0;
   const rolePingReasons = collectRolePingReasons(message);
   const rolePing = hasRolePing(message);
+  const imageOnly = isImageOnlyMessage(message);
   const reasons = [...rolePingReasons];
 
   if (hasLink) {
@@ -80,7 +129,26 @@ export function detectSpam(message, { duplicateAcrossChannels = false } = {}) {
     reasons.push("same message posted across multiple channels");
   }
 
-  const isSpam = rolePing && hasLink && duplicateAcrossChannels;
+  if (imageOnly) {
+    const images = getImageAttachments(message);
+    const preview = images
+      .slice(0, 3)
+      .map((attachment) => attachment.name || "image")
+      .join(", ");
+    reasons.push(
+      images.length > 0
+        ? `image-only message (${preview}${images.length > 3 ? ` +${images.length - 3} more` : ""})`
+        : "image-only message (stickers)"
+    );
+  }
+
+  if (duplicateImageAcrossChannels) {
+    reasons.push("image-only spam posted across multiple channels");
+  }
+
+  const isClassicSpam = rolePing && hasLink && duplicateAcrossChannels;
+  const isImageSpam = imageOnly && duplicateImageAcrossChannels;
+  const isSpam = isClassicSpam || isImageSpam;
 
   return {
     isSpam,