diff --git a/mastodon/src/main/AndroidManifest.xml b/mastodon/src/main/AndroidManifest.xml
index 15bfddb5d..bb9b716d4 100644
--- a/mastodon/src/main/AndroidManifest.xml
+++ b/mastodon/src/main/AndroidManifest.xml
@@ -33,6 +33,18 @@
 				<data android:scheme="mastodon-android-auth" android:host="callback"/>
 			</intent-filter>
 		</activity>
+		<activity android:name=".ExternalShareActivity" android:exported="true" android:configChanges="orientation|screenSize" android:windowSoftInputMode="adjustResize">
+			<intent-filter>
+				<action android:name="android.intent.action.SEND"/>
+				<category android:name="android.intent.category.DEFAULT"/>
+				<data android:mimeType="*/*"/>
+			</intent-filter>
+			<intent-filter>
+				<action android:name="android.intent.action.SEND_MULTIPLE"/>
+				<category android:name="android.intent.category.DEFAULT"/>
+				<data android:mimeType="*/*"/>
+			</intent-filter>
+		</activity>
 
 		<service android:name=".AudioPlayerService" android:foregroundServiceType="mediaPlayback"/>
 
diff --git a/mastodon/src/main/java/org/joinmastodon/android/ExternalShareActivity.java b/mastodon/src/main/java/org/joinmastodon/android/ExternalShareActivity.java
new file mode 100644
index 000000000..d2e0f27bc
--- /dev/null
+++ b/mastodon/src/main/java/org/joinmastodon/android/ExternalShareActivity.java
@@ -0,0 +1,94 @@
+package org.joinmastodon.android;
+
+import android.app.Fragment;
+import android.content.ClipData;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.graphics.drawable.ColorDrawable;
+import android.net.Uri;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.widget.Toast;
+
+import org.joinmastodon.android.api.session.AccountSession;
+import org.joinmastodon.android.api.session.AccountSessionManager;
+import org.joinmastodon.android.fragments.ComposeFragment;
+import org.joinmastodon.android.ui.M3AlertDialogBuilder;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import androidx.annotation.Nullable;
+import me.grishka.appkit.FragmentStackActivity;
+
+public class ExternalShareActivity extends FragmentStackActivity{
+	@Override
+	protected void onCreate(@Nullable Bundle savedInstanceState){
+		super.onCreate(savedInstanceState);
+		if(savedInstanceState==null){
+			List<AccountSession> sessions=AccountSessionManager.getInstance().getLoggedInAccounts();
+			if(sessions.isEmpty()){
+				Toast.makeText(this, R.string.err_not_logged_in, Toast.LENGTH_SHORT).show();
+				finish();
+			}else if(sessions.size()==1){
+				openComposeFragment(sessions.get(0).getID());
+			}else{
+				getWindow().setBackgroundDrawable(new ColorDrawable(0xff000000));
+				new M3AlertDialogBuilder(this)
+						.setItems(sessions.stream().map(as->"@"+as.self.username+"@"+as.domain).toArray(String[]::new), (dialog, which)->{
+							openComposeFragment(sessions.get(which).getID());
+						})
+						.setTitle(R.string.choose_account)
+						.setOnCancelListener(dialog -> finish())
+						.show();
+			}
+		}
+	}
+
+	private void openComposeFragment(String accountID){
+		getWindow().setBackgroundDrawable(null);
+
+		Intent intent=getIntent();
+		String text=intent.getStringExtra(Intent.EXTRA_TEXT);
+		List<Uri> mediaUris;
+		if(Intent.ACTION_SEND.equals(intent.getAction())){
+			Uri singleUri=intent.getParcelableExtra(Intent.EXTRA_STREAM);
+			mediaUris=singleUri!=null ? Collections.singletonList(singleUri) : null;
+		}else if(Intent.ACTION_SEND_MULTIPLE.equals(intent.getAction())){
+			ClipData clipData=intent.getClipData();
+			if(clipData!=null){
+				mediaUris=new ArrayList<>(clipData.getItemCount());
+				for(int i=0;i<clipData.getItemCount();i++){
+					ClipData.Item item=clipData.getItemAt(i);
+					mediaUris.add(item.getUri());
+				}
+			}else{
+				mediaUris=null;
+			}
+		}else{
+			Toast.makeText(this, "Unexpected intent action: "+intent.getAction(), Toast.LENGTH_SHORT).show();
+			finish();
+			return;
+		}
+
+		Bundle args=new Bundle();
+		args.putString("account", accountID);
+		if(!TextUtils.isEmpty(text))
+			args.putString("prefilledText", text);
+		if(mediaUris!=null && !mediaUris.isEmpty())
+			args.putParcelableArrayList("mediaAttachments", toArrayList(mediaUris));
+		Fragment fragment=new ComposeFragment();
+		fragment.setArguments(args);
+		showFragmentClearingBackStack(fragment);
+	}
+
+	private static <T> ArrayList<T> toArrayList(List<T> l){
+		if(l instanceof ArrayList)
+			return (ArrayList<T>) l;
+		if(l==null)
+			return null;
+		return new ArrayList<>(l);
+	}
+}
diff --git a/mastodon/src/main/java/org/joinmastodon/android/PushNotificationReceiver.java b/mastodon/src/main/java/org/joinmastodon/android/PushNotificationReceiver.java
index edf4e1194..d802892c8 100644
--- a/mastodon/src/main/java/org/joinmastodon/android/PushNotificationReceiver.java
+++ b/mastodon/src/main/java/org/joinmastodon/android/PushNotificationReceiver.java
@@ -125,8 +125,9 @@ public class PushNotificationReceiver extends BroadcastReceiver{
 				.setStyle(new Notification.BigTextStyle().bigText(pn.body))
 				.setSmallIcon(R.drawable.ic_ntf_logo)
 				.setContentIntent(PendingIntent.getActivity(context, accountID.hashCode() & 0xFFFF, contentIntent, PendingIntent.FLAG_IMMUTABLE | PendingIntent.FLAG_CANCEL_CURRENT))
-				.setWhen(System.currentTimeMillis())
+				.setWhen(notification==null ? System.currentTimeMillis() : notification.createdAt.toEpochMilli())
 				.setShowWhen(true)
+				.setCategory(Notification.CATEGORY_SOCIAL)
 				.setAutoCancel(true)
 				.setColor(context.getColor(R.color.primary_700));
 		if(avatar!=null){
diff --git a/mastodon/src/main/java/org/joinmastodon/android/fragments/ComposeFragment.java b/mastodon/src/main/java/org/joinmastodon/android/fragments/ComposeFragment.java
index 9eef2ae4b..b37565478 100644
--- a/mastodon/src/main/java/org/joinmastodon/android/fragments/ComposeFragment.java
+++ b/mastodon/src/main/java/org/joinmastodon/android/fragments/ComposeFragment.java
@@ -7,6 +7,7 @@ import android.content.ClipData;
 import android.content.Intent;
 import android.content.res.ColorStateList;
 import android.content.res.Configuration;
+import android.database.Cursor;
 import android.graphics.Outline;
 import android.graphics.PixelFormat;
 import android.graphics.drawable.Drawable;
@@ -17,6 +18,7 @@ import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Parcelable;
+import android.provider.OpenableColumns;
 import android.text.Editable;
 import android.text.InputFilter;
 import android.text.Layout;
@@ -51,6 +53,7 @@ import com.twitter.twittertext.Regex;
 import com.twitter.twittertext.TwitterTextEmojiRegex;
 
 import org.joinmastodon.android.E;
+import org.joinmastodon.android.MastodonApp;
 import org.joinmastodon.android.R;
 import org.joinmastodon.android.api.ProgressListener;
 import org.joinmastodon.android.api.requests.statuses.CreateStatus;
@@ -88,6 +91,7 @@ import org.parceler.Parcels;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.UUID;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -175,6 +179,7 @@ public class ComposeFragment extends ToolbarFragment implements OnBackPressedLis
 	private FrameLayout mainEditTextWrap;
 	private ComposeAutocompleteViewController autocompleteViewController;
 	private Instance instance;
+	private boolean attachmentsErrorShowing;
 
 	@Override
 	public void onCreate(Bundle savedInstanceState){
@@ -452,6 +457,12 @@ public class ComposeFragment extends ToolbarFragment implements OnBackPressedLis
 				mainEditText.setSelection(mainEditText.length());
 				initialText=prefilledText;
 			}
+			ArrayList<Uri> mediaUris=getArguments().getParcelableArrayList("mediaAttachments");
+			if(mediaUris!=null && !mediaUris.isEmpty()){
+				for(Uri uri:mediaUris){
+					addMediaAttachment(uri);
+				}
+			}
 		}
 	}
 
@@ -684,8 +695,29 @@ public class ComposeFragment extends ToolbarFragment implements OnBackPressedLis
 	}
 
 	private void addMediaAttachment(Uri uri){
-		if(getMediaAttachmentsCount()==MAX_ATTACHMENTS)
+		if(getMediaAttachmentsCount()==MAX_ATTACHMENTS){
+			showMediaAttachmentError(getResources().getQuantityString(R.plurals.cant_add_more_than_x_attachments, MAX_ATTACHMENTS, MAX_ATTACHMENTS));
 			return;
+		}
+		String type=getActivity().getContentResolver().getType(uri);
+		if(instance.configuration!=null && instance.configuration.mediaAttachments!=null){
+			if(instance.configuration.mediaAttachments.supportedMimeTypes!=null && !instance.configuration.mediaAttachments.supportedMimeTypes.contains(type)){
+				showMediaAttachmentError(getString(R.string.media_attachment_unsupported_type, UiUtils.getFileName(uri)));
+				return;
+			}
+			int sizeLimit=type.startsWith("image/") ? instance.configuration.mediaAttachments.imageSizeLimit : instance.configuration.mediaAttachments.videoSizeLimit;
+			int size;
+			try(Cursor cursor=MastodonApp.context.getContentResolver().query(uri, new String[]{OpenableColumns.SIZE}, null, null, null)){
+				cursor.moveToFirst();
+				size=cursor.getInt(0);
+			}
+			if(size>sizeLimit){
+				float mb=sizeLimit/(float)(1024*1024);
+				String sMb=String.format(Locale.getDefault(), mb%1f==0f ? "%f" : "%.2f", mb);
+				showMediaAttachmentError(getString(R.string.media_attachment_too_big, UiUtils.getFileName(uri), sMb));
+				return;
+			}
+		}
 		pollBtn.setEnabled(false);
 		DraftMediaAttachment draft=new DraftMediaAttachment();
 		draft.uri=uri;
@@ -706,6 +738,14 @@ public class ComposeFragment extends ToolbarFragment implements OnBackPressedLis
 			mediaBtn.setEnabled(false);
 	}
 
+	private void showMediaAttachmentError(String text){
+		if(!attachmentsErrorShowing){
+			Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT).show();
+			attachmentsErrorShowing=true;
+			contentView.postDelayed(()->attachmentsErrorShowing=false, 2000);
+		}
+	}
+
 	private View createMediaAttachmentView(DraftMediaAttachment draft){
 		View thumb=getActivity().getLayoutInflater().inflate(R.layout.compose_media_thumb, attachmentsView, false);
 		ImageView img=thumb.findViewById(R.id.thumb);
@@ -812,10 +852,9 @@ public class ComposeFragment extends ToolbarFragment implements OnBackPressedLis
 		DraftMediaAttachment att=(DraftMediaAttachment) v.getTag();
 		if(att==uploadingAttachment){
 			att.uploadRequest.cancel();
+			uploadingAttachment=null;
 			if(!queuedAttachments.isEmpty())
 				uploadMediaAttachment(queuedAttachments.remove(0));
-			else
-				uploadingAttachment=null;
 		}else{
 			attachments.remove(att);
 			queuedAttachments.remove(att);
diff --git a/mastodon/src/main/res/values/strings.xml b/mastodon/src/main/res/values/strings.xml
index 60c5eb3cd..64eb3fb7e 100644
--- a/mastodon/src/main/res/values/strings.xml
+++ b/mastodon/src/main/res/values/strings.xml
@@ -228,4 +228,12 @@
 	<string name="notification_type_reblog">Boosts</string>
 	<string name="notification_type_mention">Mentions</string>
 	<string name="notification_type_poll">Polls</string>
+	<string name="choose_account">Choose account</string>
+	<string name="err_not_logged_in">Please log into Mastodon first</string>
+	<plurals name="cant_add_more_than_x_attachments">
+		<item quantity="one">You can\'t add more than %d media attachment</item>
+		<item quantity="other">You can\'t add more than %d media attachments</item>
+	</plurals>
+	<string name="media_attachment_unsupported_type">File %s is of an unsupported type</string>
+	<string name="media_attachment_too_big">File %1$s exceeds the size limit of %2$s MB</string>
 </resources>
\ No newline at end of file