diff --git a/src/domain/session/room/timeline/tiles/FileTile.js b/src/domain/session/room/timeline/tiles/FileTile.js
index eab55136..c87b090f 100644
--- a/src/domain/session/room/timeline/tiles/FileTile.js
+++ b/src/domain/session/room/timeline/tiles/FileTile.js
@@ -24,12 +24,9 @@ export class FileTile extends MessageTile {
         this._error = null;
         this._downloading = false;
         if (this._isUploading) {
-            // should really do this with an ObservableValue and waitFor to prevent leaks when the promise never resolves
-            this._entry.attachment.uploaded().finally(() => {
-                if (!this.isDisposed) {
-                    this.emitChange("label");
-                }
-            });
+            this.track(this._entry.attachments.url.status.subscribe(() => {
+                this.emitChange("label");
+            }));
         }
     }
 
@@ -56,28 +53,28 @@ export class FileTile extends MessageTile {
 
     get size() {
         if (this._isUploading) {
-            return this._entry.attachment.localPreview.size;
+            return this._entry.attachments.url.localPreview.size;
         } else {
             return this._getContent().info?.size;
         }
     }
 
     get _isUploading() {
-        return this._entry.attachment && !this._entry.attachment.isUploaded;
+        return this._entry.attachments?.url && !this._entry.attachments.url.isUploaded;
     }
 
     get label() {
         if (this._error) {
             return `Could not decrypt file: ${this._error.message}`;
         }
-        if (this._entry.attachment?.error) {
-            return `Failed to upload: ${this._entry.attachment.error.message}`;
+        if (this._entry.attachments?.url?.error) {
+            return `Failed to upload: ${this._entry.attachments.url.error.message}`;
         }
         const content = this._getContent();
         const filename = content.body;
         const size = formatSize(this.size);
         if (this._isUploading) {
-            return this.i18n`Uploading ${filename} (${size})…`;
+            return this.i18n`Uploading (${this._entry.attachments.url.status.get()}) ${filename} (${size})…`;
         } else if (this._downloading) {
             return this.i18n`Downloading ${filename} (${size})…`;
         } else {
diff --git a/src/matrix/room/AttachmentUpload.js b/src/matrix/room/AttachmentUpload.js
index 98d81894..5dd957a0 100644
--- a/src/matrix/room/AttachmentUpload.js
+++ b/src/matrix/room/AttachmentUpload.js
@@ -15,6 +15,11 @@ limitations under the License.
 */
 
 import {encryptAttachment} from "../e2ee/attachment.js";
+import {createEnum} from "../../utils/enum.js";
+import {ObservableValue} from "../../observable/ObservableValue.js";
+import {AbortError} from "../../utils/error.js";
+
+export const UploadStatus = createEnum("Waiting", "Encrypting", "Uploading", "Uploaded", "Error");
 
 export class AttachmentUpload {
     constructor({filename, blob, hsApi, platform, isEncrypted}) {
@@ -26,44 +31,51 @@ export class AttachmentUpload {
         this._mxcUrl = null;
         this._transferredBlob = null;
         this._encryptionInfo = null;
-        this._uploadPromise = null;
         this._uploadRequest = null;
         this._aborted = false;
         this._error = null;
+        this._status = new ObservableValue(UploadStatus.Waiting);
     }
 
-    upload() {
-        if (!this._uploadPromise) {
-            this._uploadPromise = this._upload();
+    get status() {
+        return this._status;
+    }
+
+    async upload() {
+        if (this._status.get() === UploadStatus.Waiting) {
+            this._upload();
+        }
+        await this._status.waitFor(s => s === UploadStatus.Error || s === UploadStatus.Uploaded).promise;
+        if (this._status.get() === UploadStatus.Error) {
+            throw this._error;
         }
-        return this._uploadPromise;
     }
 
+    /** @package */
     async _upload() {
         try {
             let transferredBlob = this._unencryptedBlob;
             if (this._isEncrypted) {
+                this._status.set(UploadStatus.Encrypting);
                 const {info, blob} = await encryptAttachment(this._platform, this._unencryptedBlob);
                 transferredBlob = blob;
                 this._encryptionInfo = info;
             }
             if (this._aborted) {
-                return;
+                throw new AbortError("upload aborted during encryption");
             }
+            this._status.set(UploadStatus.Uploading);
             this._uploadRequest = this._hsApi.uploadAttachment(transferredBlob, this._filename);
             const {content_uri} = await this._uploadRequest.response();
             this._mxcUrl = content_uri;
             this._transferredBlob = transferredBlob;
+            this._status.set(UploadStatus.Uploaded);
         } catch (err) {
             this._error = err;
-            throw err;
+            this._status.set(UploadStatus.Error);
         }
     }
 
-    get isUploaded() {
-        return !!this._transferredBlob;
-    }
-
     /** @public */
     abort() {
         this._aborted = true;
@@ -80,29 +92,34 @@ export class AttachmentUpload {
     }
 
     /** @package */
-    uploaded() {
-        if (!this._uploadPromise) {
-            throw new Error("upload has not started yet");
-        }
-        return this._uploadPromise;
-    }
-
-    /** @package */
-    applyToContent(content) {
+    applyToContent(urlPath, content) {
         if (!this._mxcUrl) {
             throw new Error("upload has not finished");
         }
-        content.info = {
-            size: this._transferredBlob.size,
-            mimetype: this._unencryptedBlob.mimeType,
-        };
+        let prefix = urlPath.substr(0, urlPath.lastIndexOf("url"));
+        setPath(`${prefix}info.size`, content, this._transferredBlob.size);
+        setPath(`${prefix}info.mimetype`, content, this._unencryptedBlob.mimeType);
         if (this._isEncrypted) {
-            content.file = Object.assign(this._encryptionInfo, {
+            setPath(`${prefix}file`, content, Object.assign(this._encryptionInfo, {
                 mimetype: this._unencryptedBlob.mimeType,
                 url: this._mxcUrl
-            });
+            }));
         } else {
-            content.url = this._mxcUrl;
+            setPath(`${prefix}url`, content, this._mxcUrl);
         }
     }
 }
+
+function setPath(path, content, value) {
+    const parts = path.split(".");
+    let obj = content;
+    for (let i = 0; i < (parts.length - 1); i += 1) {
+        const key = parts[i];
+        if (!obj[key]) {
+            obj[key] = {};
+        }
+        obj = obj[key];
+    }
+    const propKey = parts[parts.length - 1];
+    obj[propKey] = value;
+}
diff --git a/src/matrix/room/Room.js b/src/matrix/room/Room.js
index 109c096e..69829e9c 100644
--- a/src/matrix/room/Room.js
+++ b/src/matrix/room/Room.js
@@ -352,8 +352,8 @@ export class Room extends EventEmitter {
     }
 
     /** @public */
-    sendEvent(eventType, content, attachment) {
-        return this._sendQueue.enqueueEvent(eventType, content, attachment);
+    sendEvent(eventType, content, attachments) {
+        return this._sendQueue.enqueueEvent(eventType, content, attachments);
     }
 
     /** @public */
@@ -633,10 +633,9 @@ export class Room extends EventEmitter {
         }
     }
 
-    uploadAttachment(blob, filename) {
+    createAttachment(blob, filename) {
         const attachment = new AttachmentUpload({blob, filename,
             hsApi: this._hsApi, platform: this._platform, isEncrypted: this.isEncrypted});
-        attachment.upload();
         return attachment;
     }
 
diff --git a/src/matrix/room/sending/PendingEvent.js b/src/matrix/room/sending/PendingEvent.js
index 030e57b6..b1e7f5a2 100644
--- a/src/matrix/room/sending/PendingEvent.js
+++ b/src/matrix/room/sending/PendingEvent.js
@@ -15,9 +15,9 @@ limitations under the License.
 */
 
 export class PendingEvent {
-    constructor(data, attachment) {
+    constructor(data, attachments) {
         this._data = data;
-        this.attachment = attachment;
+        this.attachments = attachments;
     }
 
     get roomId() { return this._data.roomId; }
diff --git a/src/matrix/room/sending/SendQueue.js b/src/matrix/room/sending/SendQueue.js
index 76ff2c66..23019358 100644
--- a/src/matrix/room/sending/SendQueue.js
+++ b/src/matrix/room/sending/SendQueue.js
@@ -51,16 +51,15 @@ export class SendQueue {
                     this._amountSent += 1;
                     continue;
                 }
-                if (pendingEvent.attachment) {
-                    const {attachment} = pendingEvent;
+                if (pendingEvent.attachments) {
                     try {
-                        await attachment.uploaded();
+                        await this._uploadAttachments(pendingEvent);
                     } catch (err) {
-                        console.log("upload failed, skip sending message", pendingEvent);
+                        console.log("upload failed, skip sending message", err, pendingEvent);
                         this._amountSent += 1;
                         continue;
                     }
-                    attachment.applyToContent(pendingEvent.content);
+                    console.log("attachments upload, content is now", pendingEvent.content);
                 }
                 if (pendingEvent.needsEncryption) {
                     const {type, content} = await this._roomEncryption.encrypt(
@@ -127,8 +126,8 @@ export class SendQueue {
         }
     }
 
-    async enqueueEvent(eventType, content, attachment) {
-        const pendingEvent = await this._createAndStoreEvent(eventType, content, attachment);
+    async enqueueEvent(eventType, content, attachments) {
+        const pendingEvent = await this._createAndStoreEvent(eventType, content, attachments);
         this._pendingEvents.set(pendingEvent);
         console.log("added to _pendingEvents set", this._pendingEvents.length);
         if (!this._isSending && !this._offline) {
@@ -161,7 +160,7 @@ export class SendQueue {
         await txn.complete();
     }
 
-    async _createAndStoreEvent(eventType, content, attachment) {
+    async _createAndStoreEvent(eventType, content, attachments) {
         console.log("_createAndStoreEvent");
         const txn = this._storage.readWriteTxn([this._storage.storeNames.pendingEvents]);
         let pendingEvent;
@@ -178,7 +177,7 @@ export class SendQueue {
                 content,
                 txnId: makeTxnId(),
                 needsEncryption: !!this._roomEncryption
-            }, attachment);
+            }, attachments);
             console.log("_createAndStoreEvent: adding to pendingEventsStore");
             pendingEventsStore.add(pendingEvent.data);
         } catch (err) {
@@ -188,4 +187,12 @@ export class SendQueue {
         await txn.complete();
         return pendingEvent;
     }
+
+    async _uploadAttachments(pendingEvent) {
+        const {attachments} = pendingEvent;
+        for (const [urlPath, attachment] of Object.entries(attachments)) {
+            await attachment.upload();
+            attachment.applyToContent(urlPath, pendingEvent.content);
+        }
+    }
 }
diff --git a/src/matrix/room/timeline/entries/PendingEventEntry.js b/src/matrix/room/timeline/entries/PendingEventEntry.js
index 9f91c80f..e31e56d5 100644
--- a/src/matrix/room/timeline/entries/PendingEventEntry.js
+++ b/src/matrix/room/timeline/entries/PendingEventEntry.js
@@ -64,8 +64,8 @@ export class PendingEventEntry extends BaseEntry {
         return this._pendingEvent.txnId;
     }
 
-    get attachment() {
-        return this._pendingEvent.attachment;
+    get attachments() {
+        return this._pendingEvent.attachments;
     }
 
     notifyUpdate() {