diff --git a/gui/src/client.ts b/gui/src/client.ts
index e68ee42c..a8198c94 100644
--- a/gui/src/client.ts
+++ b/gui/src/client.ts
@@ -129,6 +129,11 @@ export interface UpscaleReqParams {
   source: Blob;
 }
 
+export interface BlendParams {
+  sources: Array<Blob>;
+  mask: Blob;
+}
+
 /**
  * General response for most image requests.
  */
@@ -217,6 +222,11 @@ export interface ApiClient {
    */
   upscale(model: ModelParams, params: UpscaleReqParams, upscale?: UpscaleParams): Promise<ImageResponse>;
 
+  /**
+   * Start a blending pipeline.
+   */
+  blend(model: ModelParams, params: BlendParams, upscale?: UpscaleParams): Promise<ImageResponse>;
+
   /**
    * Check whether some pipeline's output is ready yet.
    */
@@ -471,6 +481,9 @@ export function makeClient(root: string, f = fetch): ApiClient {
         method: 'POST',
       });
     },
+    async blend(model: ModelParams, params: BlendParams, upscale: UpscaleParams): Promise<ImageResponse> {
+      throw new Error('TODO');
+    },
     async ready(params: ImageResponse): Promise<ReadyResponse> {
       const path = makeApiUrl(root, 'ready');
       path.searchParams.append('output', params.output.key);
diff --git a/gui/src/components/ImageCard.tsx b/gui/src/components/ImageCard.tsx
index daa95744..ec9feaa9 100644
--- a/gui/src/components/ImageCard.tsx
+++ b/gui/src/components/ImageCard.tsx
@@ -1,5 +1,5 @@
 import { doesExist, mustDefault, mustExist } from '@apextoaster/js-utils';
-import { Brush, ContentCopy, Delete, Download } from '@mui/icons-material';
+import { Blender, Brush, ContentCopy, CropFree, Delete, Download, ZoomOutMap } from '@mui/icons-material';
 import { Box, Card, CardContent, CardMedia, Grid, IconButton, Paper, Tooltip } from '@mui/material';
 import * as React from 'react';
 import { useContext } from 'react';
@@ -33,6 +33,10 @@ export function ImageCard(props: ImageCardProps) {
   const setImg2Img = useStore(state, (s) => s.setImg2Img);
   // eslint-disable-next-line @typescript-eslint/unbound-method
   const setInpaint = useStore(state, (s) => s.setInpaint);
+  // eslint-disable-next-line @typescript-eslint/unbound-method
+  const setUpscale = useStore(state, (s) => s.setUpscaleTab);
+  // eslint-disable-next-line @typescript-eslint/unbound-method
+  const setBlend = useStore(state, (s) => s.setBlend);
 
   async function loadSource() {
     const req = await fetch(output.url);
@@ -55,6 +59,23 @@ export function ImageCard(props: ImageCardProps) {
     setHash('inpaint');
   }
 
+  async function copySourceToUpscale() {
+    const blob = await loadSource();
+    setUpscale({
+      source: blob,
+    });
+    setHash('upscale');
+  }
+
+  async function copySourceToBlend() {
+    const blob = await loadSource();
+    // TODO: push instead
+    setBlend({
+      sources: [blob],
+    });
+    setHash('blend');
+  }
+
   function deleteImage() {
     if (doesExist(props.onDelete)) {
       props.onDelete(value);
@@ -86,28 +107,42 @@ export function ImageCard(props: ImageCardProps) {
           <GridItem xs={12}>
             <Box textAlign='left'>{params.prompt}</Box>
           </GridItem>
-          <GridItem xs={3}>
+          <GridItem xs={2}>
             <Tooltip title='Save'>
               <IconButton onClick={downloadImage}>
                 <Download />
               </IconButton>
             </Tooltip>
           </GridItem>
-          <GridItem xs={3}>
+          <GridItem xs={2}>
             <Tooltip title='Img2img'>
               <IconButton onClick={copySourceToImg2Img}>
                 <ContentCopy />
               </IconButton>
             </Tooltip>
           </GridItem>
-          <GridItem xs={3}>
+          <GridItem xs={2}>
             <Tooltip title='Inpaint'>
               <IconButton onClick={copySourceToInpaint}>
                 <Brush />
               </IconButton>
             </Tooltip>
           </GridItem>
-          <GridItem xs={3}>
+          <GridItem xs={2}>
+            <Tooltip title='Upscale'>
+              <IconButton onClick={copySourceToUpscale}>
+                <ZoomOutMap />
+              </IconButton>
+            </Tooltip>
+          </GridItem>
+          <GridItem xs={2}>
+            <Tooltip title='Blend'>
+              <IconButton onClick={copySourceToBlend}>
+                <Blender />
+              </IconButton>
+            </Tooltip>
+          </GridItem>
+          <GridItem xs={2}>
             <Tooltip title='Delete'>
               <IconButton onClick={deleteImage}>
                 <Delete />
diff --git a/gui/src/components/OnnxWeb.tsx b/gui/src/components/OnnxWeb.tsx
index 0c070067..bb12d607 100644
--- a/gui/src/components/OnnxWeb.tsx
+++ b/gui/src/components/OnnxWeb.tsx
@@ -6,6 +6,7 @@ import { useHash } from 'react-use/lib/useHash';
 
 import { ModelControl } from './control/ModelControl.js';
 import { ImageHistory } from './ImageHistory.js';
+import { Blend } from './tab/Blend.js';
 import { Img2Img } from './tab/Img2Img.js';
 import { Inpaint } from './tab/Inpaint.js';
 import { Settings } from './tab/Settings.js';
@@ -13,6 +14,14 @@ import { Txt2Img } from './tab/Txt2Img.js';
 import { Upscale } from './tab/Upscale.js';
 
 const REMOVE_HASH = /^#?(.*)$/;
+const TAB_LABELS = [
+  'txt2img',
+  'img2img',
+  'inpaint',
+  'upscale',
+  'blend',
+  'settings',
+];
 
 export function OnnxWeb() {
   const [hash, setHash] = useHash();
@@ -26,7 +35,7 @@ export function OnnxWeb() {
       }
     }
 
-    return 'txt2img';
+    return TAB_LABELS[0];
   }
 
   return (
@@ -44,11 +53,7 @@ export function OnnxWeb() {
           <TabList onChange={(_e, idx) => {
             setHash(idx);
           }}>
-            <Tab label='txt2img' value='txt2img' />
-            <Tab label='img2img' value='img2img' />
-            <Tab label='inpaint' value='inpaint' />
-            <Tab label='upscale' value='upscale' />
-            <Tab label='settings' value='settings' />
+            {TAB_LABELS.map((name) => <Tab key={name} label={name} value={name} />)}
           </TabList>
         </Box>
         <TabPanel value='txt2img'>
@@ -63,6 +68,9 @@ export function OnnxWeb() {
         <TabPanel value='upscale'>
           <Upscale />
         </TabPanel>
+        <TabPanel value='blend'>
+          <Blend />
+        </TabPanel>
         <TabPanel value='settings'>
           <Settings />
         </TabPanel>
diff --git a/gui/src/components/tab/Blend.tsx b/gui/src/components/tab/Blend.tsx
new file mode 100644
index 00000000..51660eb2
--- /dev/null
+++ b/gui/src/components/tab/Blend.tsx
@@ -0,0 +1,70 @@
+import { doesExist, mustDefault, mustExist } from '@apextoaster/js-utils';
+import { Box, Button, Stack } from '@mui/material';
+import * as React from 'react';
+import { useContext } from 'react';
+import { useMutation, useQueryClient } from 'react-query';
+import { useStore } from 'zustand';
+
+import { IMAGE_FILTER } from '../../config.js';
+import { ClientContext, StateContext } from '../../state.js';
+import { UpscaleControl } from '../control/UpscaleControl.js';
+import { ImageInput } from '../input/ImageInput.js';
+import { MaskCanvas } from '../input/MaskCanvas.js';
+
+export function Blend() {
+  async function uploadSource() {
+    const { model, blend, upscale } = state.getState();
+
+    const output = await client.blend(model, {
+      ...blend,
+      mask: mustExist(blend.mask),
+      sources: mustExist(blend.sources), // TODO: show an error if this doesn't exist
+    }, upscale);
+
+    setLoading(output);
+  }
+
+  const client = mustExist(useContext(ClientContext));
+  const query = useQueryClient();
+  const upload = useMutation(uploadSource, {
+    onSuccess: () => query.invalidateQueries({ queryKey: 'ready' }),
+  });
+
+  const state = mustExist(useContext(StateContext));
+  const blend = useStore(state, (s) => s.blend);
+  // eslint-disable-next-line @typescript-eslint/unbound-method
+  const setBlend = useStore(state, (s) => s.setBlend);
+  // eslint-disable-next-line @typescript-eslint/unbound-method
+  const setLoading = useStore(state, (s) => s.pushLoading);
+
+  const sources = mustDefault(blend.sources, []);
+
+  return <Box>
+    <Stack spacing={2}>
+      <ImageInput
+        filter={IMAGE_FILTER}
+        image={sources[0]}
+        hideSelection={true}
+        label='Source'
+        onChange={(file) => {
+          setBlend({
+            sources: [file],
+          });
+        }}
+      />
+      <MaskCanvas
+        source={sources[0]}
+        mask={blend.mask}
+        onSave={() => {
+          // TODO
+        }}
+      />
+      <UpscaleControl />
+      <Button
+        disabled={sources.length === 0}
+        variant='contained'
+        onClick={() => upload.mutate()}
+      >Generate</Button>
+    </Stack>
+  </Box>;
+}
diff --git a/gui/src/config.ts b/gui/src/config.ts
index 0442deb1..1d46f815 100644
--- a/gui/src/config.ts
+++ b/gui/src/config.ts
@@ -25,7 +25,7 @@ export type KeyFilter<T extends object, TValid = number | string> = {
  * Keep fields with a file-like value, but make them optional.
  */
 export type ConfigFiles<T extends object> = {
-  [K in KeyFilter<T, Blob | File>]: Maybe<T[K]>;
+  [K in KeyFilter<T, Blob | File | Array<Blob | File>>]: Maybe<T[K]>;
 };
 
 /**
diff --git a/gui/src/main.tsx b/gui/src/main.tsx
index 1eb8a690..2e3ec476 100644
--- a/gui/src/main.tsx
+++ b/gui/src/main.tsx
@@ -47,6 +47,7 @@ export async function main() {
         createOutpaintSlice,
         createTxt2ImgSlice,
         createUpscaleSlice,
+        createBlendSlice,
         createResetSlice,
       } = createStateSlices(params);
       const state = createStore<OnnxState, [['zustand/persist', OnnxState]]>(persist((...slice) => ({
@@ -59,6 +60,7 @@ export async function main() {
         ...createTxt2ImgSlice(...slice),
         ...createOutpaintSlice(...slice),
         ...createUpscaleSlice(...slice),
+        ...createBlendSlice(...slice),
         ...createResetSlice(...slice),
       }), {
         name: 'onnx-web',
diff --git a/gui/src/state.ts b/gui/src/state.ts
index 0dd9a6a4..854bf964 100644
--- a/gui/src/state.ts
+++ b/gui/src/state.ts
@@ -1,3 +1,4 @@
+/* eslint-disable max-lines */
 /* eslint-disable no-null/no-null */
 import { doesExist, Maybe } from '@apextoaster/js-utils';
 import { createContext } from 'react';
@@ -6,6 +7,7 @@ import { StateCreator, StoreApi } from 'zustand';
 import {
   ApiClient,
   BaseImgParams,
+  BlendParams,
   BrushParams,
   ImageResponse,
   Img2ImgParams,
@@ -100,6 +102,13 @@ interface UpscaleSlice {
   resetUpscaleTab(): void;
 }
 
+interface BlendSlice {
+  blend: TabState<BlendParams>;
+
+  setBlend(blend: Partial<BlendParams>): void;
+  resetBlend(): void;
+}
+
 interface ResetSlice {
   resetAll(): void;
 }
@@ -118,6 +127,7 @@ export type OnnxState
   & OutpaintSlice
   & Txt2ImgSlice
   & UpscaleSlice
+  & BlendSlice
   & ResetSlice;
 
 /**
@@ -419,6 +429,29 @@ export function createStateSlices(server: ServerParams) {
     },
   });
 
+  const createBlendSlice: Slice<BlendSlice> = (set) => ({
+    blend: {
+      mask: null,
+      sources: [],
+    },
+    setBlend(blend) {
+      set((prev) => ({
+        blend: {
+          ...prev.blend,
+          ...blend,
+        },
+      }));
+    },
+    resetBlend() {
+      set((prev) => ({
+        blend: {
+          mask: null,
+          sources: [],
+        },
+      }));
+    },
+  });
+
   const createDefaultSlice: Slice<DefaultSlice> = (set) => ({
     defaults: {
       ...base,
@@ -459,6 +492,7 @@ export function createStateSlices(server: ServerParams) {
         next.resetInpaint();
         next.resetTxt2Img();
         next.resetUpscaleTab();
+        next.resetBlend();
         // TODO: reset more stuff
         return next;
       });
@@ -475,6 +509,7 @@ export function createStateSlices(server: ServerParams) {
     createOutpaintSlice,
     createTxt2ImgSlice,
     createUpscaleSlice,
+    createBlendSlice,
     createResetSlice,
   };
 }