diff --git a/app/src/main/java/jp/juggler/subwaytooter/ActColumnCustomize.kt b/app/src/main/java/jp/juggler/subwaytooter/ActColumnCustomize.kt
index c861a439..280c0dae 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/ActColumnCustomize.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/ActColumnCustomize.kt
@@ -1,6 +1,5 @@
 package jp.juggler.subwaytooter
 
-import android.content.Context
 import android.content.Intent
 import android.graphics.Bitmap
 import android.net.Uri
@@ -18,6 +17,10 @@ import android.widget.TextView
 
 import com.jrummyapps.android.colorpicker.ColorPickerDialog
 import com.jrummyapps.android.colorpicker.ColorPickerDialogListener
+import jp.juggler.subwaytooter.api.TootApiClient
+import jp.juggler.subwaytooter.api.TootApiResult
+import jp.juggler.subwaytooter.api.TootTask
+import jp.juggler.subwaytooter.api.TootTaskRunner
 import jp.juggler.subwaytooter.util.*
 import org.apache.commons.io.IOUtils
 import java.io.File
@@ -25,6 +28,7 @@ import java.io.FileOutputStream
 
 import java.text.NumberFormat
 import java.util.Locale
+import kotlin.math.max
 
 class ActColumnCustomize : AppCompatActivity(), View.OnClickListener, ColorPickerDialogListener {
 	
@@ -183,7 +187,7 @@ class ActColumnCustomize : AppCompatActivity(), View.OnClickListener, ColorPicke
 			}
 			
 			R.id.btnColumnBackgroundImage -> {
-				val intent = intentOpenDocument("image/*")
+				val intent = intentGetContent(false, getString(R.string.pick_image), "image/*")
 				startActivityForResult(intent, REQUEST_CODE_PICK_BACKGROUND)
 			}
 			
@@ -221,24 +225,76 @@ class ActColumnCustomize : AppCompatActivity(), View.OnClickListener, ColorPicke
 	
 	override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
 		if(requestCode == REQUEST_CODE_PICK_BACKGROUND && data != null && resultCode == RESULT_OK) {
-			data.handleGetContentResult(contentResolver).firstOrNull()?.let { pair->
-				try{
-					val backgroundDir = getDir(Column.DIR_BACKGROUND_IMAGE, Context.MODE_PRIVATE)
-					val file = File(backgroundDir,column.column_id)
-					FileOutputStream(file).use{ outStream->
-						contentResolver.openInputStream(pair.first).use{ inStream->
-							IOUtils.copy(inStream,outStream)
-						}
-					}
-					column.column_bg_image = Uri.fromFile(file).toString()
-					show()
-				}catch(ex:Throwable){
-					showToast(this@ActColumnCustomize,true,ex.withCaption("can't update background image."))
-				}
+			data.handleGetContentResult(contentResolver).firstOrNull()?.let { pair ->
+				updateBackground(pair.first)
 			}
 		}
 	}
 	
+	private fun updateBackground(uriArg : Uri) {
+		TootTaskRunner(this).run(object : TootTask {
+			override fun background(client : TootApiClient) : TootApiResult? {
+				try {
+					val backgroundDir = Column.getBackgroundImageDir(this@ActColumnCustomize)
+					val file =
+						File(backgroundDir, "${column.column_id}:${System.currentTimeMillis()}")
+					val fileUri = Uri.fromFile(file)
+
+					client.publishApiProgress("loading image from ${uriArg}")
+					contentResolver.openInputStream(uriArg).use { inStream ->
+						FileOutputStream(file).use { outStream ->
+							IOUtils.copy(inStream, outStream)
+						}
+					}
+					
+					// リサイズや回転が必要ならする
+					client.publishApiProgress("check resize/rotation…")
+					
+					val size = (max(
+						resources.displayMetrics.widthPixels,
+						resources.displayMetrics.heightPixels
+					) * 1.5f ).toInt()
+					
+					val bitmap = createResizedBitmap(
+						this@ActColumnCustomize,
+						fileUri,
+						size,
+						skipIfNoNeedToResizeAndRotate = true
+					)
+					if(bitmap != null) {
+						try {
+							client.publishApiProgress("save resized(${bitmap.width}x${bitmap.height}) image to ${file}")
+							FileOutputStream(file).use { os ->
+								bitmap.compress(Bitmap.CompressFormat.PNG, 100, os)
+							}
+						}finally{
+							bitmap.recycle()
+						}
+					}
+					
+					val result = TootApiResult()
+					result.data = fileUri.toString()
+					return result
+				} catch(ex : Throwable) {
+					log.trace(ex)
+					return TootApiResult(ex.withCaption("can't update background image."))
+				}
+			}
+			
+			override fun handleResult(result : TootApiResult?) {
+				when {
+					result == null -> return
+					result.error != null -> showToast(this@ActColumnCustomize, true, result.error)
+					
+					else -> {
+						column.column_bg_image = result.data as String
+						show()
+					}
+				}
+			}
+		})
+	}
+	
 	private fun initUI() {
 		setContentView(R.layout.act_column_customize)
 		
@@ -443,7 +499,7 @@ class ActColumnCustomize : AppCompatActivity(), View.OnClickListener, ColorPicke
 			// 画像をロードして、成功したら表示してURLを覚える
 			val resize_max = (0.5f + 64f * density).toInt()
 			val uri = Uri.parse(url)
-			last_image_bitmap = createResizedBitmap( this, uri, resize_max )
+			last_image_bitmap = createResizedBitmap(this, uri, resize_max)
 			if(last_image_bitmap != null) {
 				ivColumnBackground.setImageBitmap(last_image_bitmap)
 				last_image_uri = url
diff --git a/app/src/main/java/jp/juggler/subwaytooter/AppState.kt b/app/src/main/java/jp/juggler/subwaytooter/AppState.kt
index 792c349f..e1005211 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/AppState.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/AppState.kt
@@ -225,7 +225,7 @@ class AppState(internal val context : Context, internal val pref : SharedPrefere
 			
 		}
 		
-		internal fun restartTTS() {
+		fun restartTTS() {
 			log.d("restart TextToSpeech")
 			tts?.shutdown()
 			tts = null
@@ -280,11 +280,13 @@ class AppState(internal val context : Context, internal val pref : SharedPrefere
 		enableSpeech()
 		
 		// 背景フォルダの掃除
-		val backgroundDir = context.getDir(Column.DIR_BACKGROUND_IMAGE,Context.MODE_PRIVATE)
-		backgroundDir.list().forEach {name->
-			val file = File(backgroundDir,name)
+		val backgroundImageDir = Column.getBackgroundImageDir(context)
+		backgroundImageDir.list().forEach {name->
+			val file = File(backgroundImageDir,name)
 			if( file.isFile ){
-				val column = Column.findColumnById( name )
+				val delm = name.indexOf(':')
+				val id = if(delm!=-1) name.substring(0, delm) else name
+				val column = Column.findColumnById( id )
 				if( column == null) file.delete()
 			}
 		}
@@ -330,7 +332,7 @@ class AppState(internal val context : Context, internal val pref : SharedPrefere
 			log.d("initializing TextToSpeech…")
 			
 			object : AsyncTask<Void, Void, TextToSpeech?>() {
-				internal var tmp_tts : TextToSpeech? = null
+				var tmp_tts : TextToSpeech? = null
 				
 				override fun doInBackground(vararg params : Void) : TextToSpeech {
 					val tts = TextToSpeech(context, tts_init_listener)
@@ -338,7 +340,7 @@ class AppState(internal val context : Context, internal val pref : SharedPrefere
 					return tts
 				}
 				
-				internal val tts_init_listener : TextToSpeech.OnInitListener =
+				val tts_init_listener : TextToSpeech.OnInitListener =
 					TextToSpeech.OnInitListener { status ->
 						
 						val tts = this.tmp_tts
diff --git a/app/src/main/java/jp/juggler/subwaytooter/Column.kt b/app/src/main/java/jp/juggler/subwaytooter/Column.kt
index c3090aa9..3bb2bb69 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/Column.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/Column.kt
@@ -4,6 +4,7 @@ import android.annotation.SuppressLint
 import android.content.Context
 import android.net.Uri
 import android.os.AsyncTask
+import android.os.Environment
 import android.os.SystemClock
 import android.view.Gravity
 import jp.juggler.subwaytooter.api.*
@@ -13,6 +14,7 @@ import jp.juggler.subwaytooter.util.*
 import org.json.JSONArray
 import org.json.JSONException
 import org.json.JSONObject
+import java.io.File
 import java.lang.ref.WeakReference
 import java.nio.ByteBuffer
 import java.text.SimpleDateFormat
@@ -55,7 +57,7 @@ class Column(
 	companion object {
 		private val log = LogCategory("Column")
 		
-		const val DIR_BACKGROUND_IMAGE = "columnBackground"
+		private const val DIR_BACKGROUND_IMAGE = "columnBackground"
 		
 		private const val READ_LIMIT = 80 // API側の上限が80です。ただし指定しても40しか返ってこないことが多い
 		private const val LOOP_TIMEOUT = 10000L
@@ -403,6 +405,28 @@ class Column(
 				return columnIdMap[id]?.get()
 			}
 		}
+		
+		fun getBackgroundImageDir(context : Context) : File {
+			val externalDir = context.getExternalFilesDir(Environment.DIRECTORY_PICTURES)
+			if( externalDir == null) {
+				log.e("getExternalFilesDir is null.")
+			}else{
+				val state = Environment.getExternalStorageState()
+				if( state != Environment.MEDIA_MOUNTED ){
+					log.e("getExternalStorageState: ${state}")
+				}else {
+					log.i("externalDir: ${externalDir}")
+					externalDir.mkdir()
+					val backgroundDir = File(externalDir,DIR_BACKGROUND_IMAGE)
+					backgroundDir.mkdir()
+					log.i("backgroundDir: ${backgroundDir} exists=${backgroundDir.exists()}")
+					return backgroundDir
+				}
+			}
+			val backgroundDir = context.getDir(Column.DIR_BACKGROUND_IMAGE,Context.MODE_PRIVATE)
+			log.i("backgroundDir: ${backgroundDir} exists=${backgroundDir.exists()}")
+			return backgroundDir
+		}
 	}
 	
 	private var callback_ref : WeakReference<Callback>? = null
@@ -2196,15 +2220,15 @@ class Column(
 						
 						TYPE_DOMAIN_BLOCKS -> return parseDomainList(client, PATH_DOMAIN_BLOCK)
 						
-						TYPE_LIST_LIST -> if(isMisskey){
+						TYPE_LIST_LIST -> return if(isMisskey){
 							val params = makeMisskeyBaseParameter(parser)
-							return parseListList(
+							parseListList(
 								client,
 								"/api/users/lists/list",
 								misskeyParams = params
 							)
 						}else{
-							return parseListList(client, PATH_LIST_LIST)
+							parseListList(client, PATH_LIST_LIST)
 							
 						}