How to use it
Drop in a picture, paste one, or choose a size and press Create for a blank canvas; the small sizes are for pixel art. The tools are down the left (each has a letter: B brush, V move, M select, C crop), their settings run along the top, and the colours, layers and history sit on the right. Scroll or pinch to zoom, and hold Space and drag to move around. Every change can be undone with Ctrl+Z, or by clicking an earlier step in History. Help lists every shortcut.
Layers, selections and effects
Each layer has its own opacity and blend mode (multiply, screen, overlay and the rest), and can be hidden, locked, merged or dragged into a new order. Select with a rectangle, an ellipse, a lasso or the magic wand; Shift adds to a selection and Alt takes away. Painting, fills and effects then stay inside it, and Ctrl+T scales, turns or flips it. The Adjust and Effects menus (levels, curves, hue, blur, sharpen and more) show a live preview before you apply them. Image holds crop, image size, canvas size, rotate and flip, which change every layer at once.
Animation and saving
The timeline along the bottom holds frames, each with its own cel on every layer and its own timing. Add or copy frames, drag them into order, turn on onion skin to see the frames either side, and press play. File, Export saves a PNG, JPG or WebP (with the exact file size shown before you download), an animated GIF, the frames as PNGs in a ZIP, or a sprite sheet. Save project keeps everything, layers and frames included, in one .wtbimg file you can open here again.
Brushes, retouching and pixel-art helpers
The button beside the Brush's name picks a tip: hard or soft round, a square pixel tip, chalk or splatter. S is the clone stamp (Alt-click where to copy from, or press Set source and tap on a phone), R switches between blur, sharpen and smudge, O between dodge, burn and sponge, and A is the spray can, which keeps spraying while you hold still. For pixel art, the Pencil's Shading ink steps each pixel to the next colour in the Colour panel's palette (right button for the previous one), the bucket and gradient can dither in 2×2, 4×4 or 8×8 patterns, Symmetry in the options bar mirrors strokes across an axis you drag or type, and View, Tile mode shows copies round the picture and wraps strokes and fills across its edges for seamless tiles. Each stroke is one step in History, and all of them keep to the selection.
Watermarks, collages, posters and pixel-art palettes
Image, Watermark adds text or a logo on a layer of its own: pick a corner or the middle, nudge it in from the edge, set its size, opacity and angle, or tile it across the picture. File, Batch watermark puts the same mark on a stack of photos and saves them in a ZIP. File, New collage lays two to nine pictures out in a grid with a gap, rounded corners and a background, each on its own layer. File, Print as poster spreads the picture over several A4 or Letter sheets in a PDF, with an overlap to glue and cut marks. File, Photo info shows a photo's camera, settings and the place it was taken, and can save a copy of a JPG, PNG or WebP without them while keeping every pixel. For pixel art, the Palette panel has PICO-8, DawnBringer, Endesga 32, Game Boy and more, reads and writes .gpl, .hex and .pal files, and Image, Reduce colours to palette maps a picture onto one, with or without dithering. Sprite sheets and folders of frames import as animation frames, and animations export as GIF (with dithering and transparency choices), APNG or, where the browser can record it, WebM video.
Masks, groups, text and layer styles
A layer mask (the circle button under the layers, or the Layer menu) hides part of a layer without rubbing it out: click the mask's thumbnail and paint black to hide, white to show and grey for in between, then click the layer's own thumbnail to paint the layer again. Groups gather layers into a folder with one opacity, blend mode and eye; Ctrl-click rows to pick several and press Ctrl+G, and drag a layer onto a group to put it in. Text stays editable on its own layer: click it with the Text tool to change the words, font, size or colour, or drag it to move it. Layer style adds a drop shadow, an outer glow or an outline that follows the layer as you paint. Select can feather, grow, shrink or border a selection, or pick a colour across the whole picture, and Ctrl-click on a thumbnail selects that layer's pixels.
Questions
Is my picture uploaded?
No. It is opened, edited and saved in this page, on your device, and nothing is sent anywhere. Nothing is kept either: close the tab and it is gone, so save the project if you want to carry on later. The page warns you before you leave with unsaved changes.
Can it replace Photoshop or Aseprite?
For a lot of everyday work, yes: layers with masks, groups and styles, blend modes, selections, levels and curves, editable text, retouching brushes, and frame-by-frame pixel art with onion skin and GIF or APNG export. It does not open PSD files, and there are no adjustment layers or brushes loaded from files yet.
How big a picture can it handle?
That depends on your device's memory. A 12-megapixel photo with a few layers is fine on a laptop or a recent phone. Undo keeps as many steps as fit in a set amount of memory, so on a very large picture the oldest steps are let go first.
Why does my saved file have no location or camera details?
Pictures are saved fresh from their pixels, so the camera, date and location details (EXIF) are left behind, which is usually what you want before sharing. File, Photo info shows those details for a photo, and can save a copy without them while keeping every pixel. To fit a picture to a social network's sizes, the Social Media Image Resizer does it in one step.