diff --git a/lib/group.ts b/lib/group.ts
index aa4b9ef0..135ceab0 100644
--- a/lib/group.ts
+++ b/lib/group.ts
@@ -49,7 +49,7 @@ export class Discuss extends Contactable {
 	async sendMsg(content: Sendable): Promise<MessageRet> {
 		const { rich, brief } = await this._preprocess(content)
 		const body = pb.encode({
-			1: { 4: { 1: this.gid } },
+			1: { 2: { 1: this.gid } },
 			2: PB_CONTENT,
 			3: { 1: rich },
 			4: randomBytes(2).readUInt16BE(),
diff --git a/lib/message/image.ts b/lib/message/image.ts
index 211afdca..07b39556 100644
--- a/lib/message/image.ts
+++ b/lib/message/image.ts
@@ -236,7 +236,7 @@ export class Image {
 			}
 		} else {
 			proto = {
-				2: this.md5.toString("hex") + ".gif",
+				2: this.md5.toString("hex") + ".jpg",
 				7: this._fid,
 				8: 0,
 				9: 0,