A report has several screenshots, a design review has two versions to compare, or a product listing needs a sheet of different angles. The images are ready, but they are separate files. MergePng addresses that small, practical job: putting multiple PNGs into one image without opening a general-purpose graphics editor.
The developer describes the tool as free and says it processes files on the user's device. Its browser-based PNG merger is built around three arrangements: a horizontal strip, a vertical stack, or a grid. That makes it useful for combining images into a single file, rather than editing the images themselves.
From files to one image
The workflow is direct. Add PNGs by dragging them into the workspace or choosing them from the device, then arrange their order. The page describes drag-and-drop ordering, along with natural filename sorting and reverse order. A preview lets you inspect the composition before downloading it.
The layout is the main decision. Horizontal places images side by side, which suits comparisons or product angles. Vertical stacks them into a longer image, a reasonable fit for tutorial steps or a sequence of screenshots. Grid arranges images in a compact sheet. These are fixed kinds of composition, not a freeform canvas: the point is to join images in a chosen arrangement with less setup than a full image editor requires.
There are some controls around that basic job. For sizing, the interface offers matching image heights, keeping original dimensions, or setting a custom height. Spacing, outer padding, background, and border width affect how the combined image sits. The preview is important here: filenames and layout choices do not tell you whether the result has the balance or spacing you want.
A merger, not a general image editor
MergePng is narrow by design. It does not, as described, offer tools for retouching, drawing, cropping, or making detailed layer adjustments. If a screenshot needs annotation or two images need careful masking, this is not the whole workflow. It can assemble the files, but another tool would be needed for that kind of editing.
There is also a distinction between the advertised image formats and the input the page actually describes. The submission mentions PNG, JPG, and WebP images, but the landing page's file picker says it supports PNG. Its export settings offer PNG, JPG, or WebP. In other words, the page supports saving the combined result in those formats, but a reader should not assume that JPG or WebP source files can be added. PNG is the safe assumption for input.
PNG output is the relevant choice when the result needs transparency. The page says transparent backgrounds can be retained when the background is set to transparent and the export format is PNG. JPG does not preserve transparency, so it requires a solid background. Switching output formats is a convenience, not a substitute for choosing the right format for the image.
What local processing does and does not promise
The developer says that files are decoded, previewed, and exported in the browser rather than uploaded to a conversion server. That may suit people combining private screenshots or unfinished design work. It also means the work depends on the device and browser doing the processing. The page warns that large outputs can run into memory or canvas-dimension limits, and that practical limits vary by device. It describes checking output size before export, but does not make large image sets unlimited.
Local processing is a useful property, but it should not be mistaken for a broad privacy guarantee. The product's claim is specifically that the source images stay on the device during merging. Anyone handling sensitive material still needs to consider the rest of their browser and device environment.
MergePng is free, requires no sign-up according to its description, and adds no watermark. For someone who regularly needs to combine a handful of PNGs into a comparison, sequence, or simple image sheet, that covers the core task with few decisions. It is for people who want assembly, not image editing. It is a poor fit for users who need JPG or WebP source files, precise freeform layouts, or dependable handling of very large collections.
Merge PNGs and images privately in your browser