How to resize, convert and rename a whole folder of photos at once
On Windows, Microsoft’s free PowerToys adds Image Resizer and PowerRename to File Explorer; on a Mac, Preview resizes a selection and Finder renames it with a number. For one job that resizes, converts and renames together, use a batch tool such as ImageMagick, and always write the results to a new folder.
30 October 2026 · 4 min read
Decide the size first
Give the longest side, not a width and height, so tall and wide pictures both fit. For a website, 1200 to 2000 pixels on the longest side is plenty; for an email attachment, 1200 or less. JPEG quality around 80 to 85 out of 100 is hard to tell from the original at a fraction of the size. PNG suits logos and screenshots; photographs are better as JPEG or WebP.
On Windows
- PowerToys Image Resizer (free, from Microsoft): select the pictures in File Explorer, right-click, Resize with Image Resizer, choose a size and whether to replace the originals or make copies.
- File Explorer renaming: select the files, press F2, type a name, and Windows numbers them Name (1), Name (2) and so on.
- PowerToys PowerRename does the same with find and replace, numbering and patterns, and shows the new names before it changes anything.
On a Mac
- Preview: open the pictures together, select all in the sidebar, Tools, Adjust Size. To change format, File, Export Selected Images.
- Finder: select the files, right-click, Rename, then Format with a name and an index number.
Doing it all in one pass
ImageMagick is free and open source on every system. In a folder of PNG pictures, magick mogrify -path ../web -resize "1200x1200>" -quality 82 -strip -format jpg *.png writes JPEG copies into an existing folder called web, shrunk to fit 1200 pixels either way (the > leaves smaller pictures alone), at quality 82 and with their metadata stripped. IrfanView and XnConvert do the same from a window, and are free for personal use but need a licence in a business.
Things to watch
- Work on copies. A batch that overwrites the originals cannot be undone.
- Transparency. PNG to JPEG fills transparent areas with a solid colour, usually white or black. Check a logo before converting a folder of them.
- Hidden details. Photos from a phone carry the camera, the date and often the place they were taken. Strip it for anything you publish.
- Names. A running number that starts at 001 sorts correctly; one that starts at 1 puts 10 before 2 in some programs.
Our own product, disclosed
Where our own software comes into this
We make Rutba Office, a free desktop suite for Windows. Its Pictures app does this from one dialog: pick a folder’s pictures, give the longest side, the format and the quality, a new name with a running number, and leave out the camera details. The originals are never changed, and a name that already exists in the folder is not written over without asking.
Related
How to remove the location from a photo before you share it
Phones write where each photo was taken into the file itself, as GPS coordinates among its EXIF details. Turn it off when sharing from the phone, use Remove Properties in Windows, or export a copy without it. Most social networks strip it from what they show, but files sent as attachments keep it.
How to rotate a photo without losing quality
Turning a JPEG in an ordinary editor and saving it compresses the picture again, and each save loses a little more. There are two ways to turn one that lose nothing: change the orientation tag the camera wrote, or turn the compressed blocks themselves. A PNG can be turned and saved as often as you like.
How to open HEIC photos and camera RAW files on Windows
Windows opens HEIC photos once two Microsoft Store extensions are installed, HEIF Image Extensions and HEVC Video Extensions, and camera RAW files once the free Raw Image Extension is. Or have the iPhone save JPEG in the first place, or convert its photos as you copy them.
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