diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/ReaderScreen.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/ReaderScreen.kt
index fdd47f57b..a1756a9b5 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/ReaderScreen.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/ReaderScreen.kt
@@ -78,6 +78,7 @@ fun ReaderScreen(info: BaseGalleryInfo, page: Int = -1) {
     }
     val showSeekbar by Settings.showReaderSeekbar.collectAsState()
     val readingMode by Settings.readingMode.collectAsState { ReadingModeType.fromPreference(it) }
+    val defaultError = stringResource(id = R.string.decode_image_error)
     Deferred({ pageLoader.awaitReady() }) {
         val lazyListState = rememberLazyListState()
         val pagerState = rememberPagerState { pageLoader.size }
@@ -134,7 +135,11 @@ fun ReaderScreen(info: BaseGalleryInfo, page: Int = -1) {
                                 painter = painter,
                                 contentDescription = null,
                                 modifier = Modifier.fillMaxWidth(),
-                                contentScale = ContentScale.FillWidth,
+                                contentScale = if (readingMode == ReadingModeType.VERTICAL) {
+                                    ContentScale.Fit
+                                } else {
+                                    ContentScale.FillWidth
+                                },
                             )
                         }
                         ERROR -> {
@@ -143,7 +148,7 @@ fun ReaderScreen(info: BaseGalleryInfo, page: Int = -1) {
                                     modifier = Modifier.align(Companion.Center),
                                     horizontalAlignment = Alignment.CenterHorizontally,
                                 ) {
-                                    Text(text = page.errorMsg.orEmpty())
+                                    Text(text = page.errorMsg ?: defaultError)
                                     Button(onClick = { }) {
                                         Text(text = stringResource(id = R.string.action_retry))
                                     }
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/SliderPagerDoubleSync.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/SliderPagerDoubleSync.kt
index 5d19cb1cb..c4dce7fd4 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/SliderPagerDoubleSync.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/SliderPagerDoubleSync.kt
@@ -13,6 +13,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshotFlow
 import com.hippo.ehviewer.gallery.PageLoader2
+import kotlin.math.absoluteValue
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.mapNotNull
 
@@ -41,7 +42,9 @@ class SliderPagerDoubleSync(
                 snapshotFlow {
                     lazyListState.layoutInfo
                 }.mapNotNull { info ->
-                    info.visibleItemsInfo.lastOrNull()
+                    info.visibleItemsInfo.lastOrNull {
+                        it.offset <= maxOf(info.viewportStartOffset, info.viewportEndOffset - it.size)
+                    }
                 }.collect { info ->
                     sliderValue = info.index + 1
                     pageLoader.startPage = info.index
@@ -49,24 +52,30 @@ class SliderPagerDoubleSync(
             }
             LaunchedEffect(Unit) {
                 snapshotFlow {
-                    pagerState.layoutInfo
-                }.mapNotNull { info ->
-                    info.visiblePagesInfo.lastOrNull()
-                }.collect { info ->
-                    sliderValue = info.index + 1
-                    pageLoader.startPage = info.index
+                    pagerState.currentPage
+                }.collect { index ->
+                    sliderValue = index + 1
+                    pageLoader.startPage = index
                 }
             }
         } else {
             LaunchedEffect(Unit) {
                 snapshotFlow { sliderValue - 1 }.collectLatest { index ->
-                    pagerState.animateScrollToPage(index)
+                    if ((index - pagerState.currentPage).absoluteValue > SMOOTH_SCROLL_THRESHOLD) {
+                        pagerState.scrollToPage(index)
+                    } else {
+                        pagerState.animateScrollToPage(index)
+                    }
                     pageLoader.startPage = index
                 }
             }
             LaunchedEffect(Unit) {
                 snapshotFlow { sliderValue - 1 }.collectLatest { index ->
-                    lazyListState.animateScrollToItem(index)
+                    if ((index - lazyListState.firstVisibleItemIndex).absoluteValue > SMOOTH_SCROLL_THRESHOLD) {
+                        lazyListState.scrollToItem(index)
+                    } else {
+                        lazyListState.animateScrollToItem(index)
+                    }
                     pageLoader.startPage = index
                 }
             }
@@ -91,3 +100,5 @@ fun rememberSliderPagerDoubleSyncState(
         SliderPagerDoubleSync(lazyListState, pagerState, pageLoader)
     }
 }
+
+private const val SMOOTH_SCROLL_THRESHOLD = 50