Resizing photos one by one is slow. You also miss files and get sizes wrong.
This guide shows you how to do a whole folder in one go with the Pi7 Bulk Image Resizer. It takes about two minutes.
The tool runs in your browser. Nothing is uploaded, and there is no cap on how many photos you add.
Open the bulk image resizer. Click Select Images or drag a folder onto the page.
You can pick hundreds of files at once. PNG, JPEG, WEBP and SVG all work in the same batch.
Forgot a few? Add More Images adds to your list. You do not start over.
This choice decides whether your photos come out right.
Pixels (px) sets an exact size for every photo. Use it when you have a number to hit. A 1200 px blog width. A 512 px profile picture.
Percentage % shrinks each photo by a share of its own size. Use it when your photos are different sizes.
Say your photos are all different sizes. Set 50% and each one halves. Force them all to one width instead and the small ones get stretched.
Leave Maintain Aspect Ratio ticked. Type only the width. The height fills in for you.
That is what stops photos looking squashed or stretched. Only turn it off if you need both numbers fixed.
Need one photo at a different size? Click the width or height next to it and type a new number. No second run needed.
Resizing already cuts file size a lot. Compression cuts it more.
Tick Compress Image and a quality slider shows up. Set it to 70-80%. That is the best trade in most cases.
Below 50% you start to see mess around text and sharp edges. Try 80% first and compare.
The Output setting changes the format on the way out:
Click Resize Images. Each photo updates as it finishes.
You can rename files before you save. Click a name and type. Handy when your camera named them DSC_0491.
Then click Download All Images for one ZIP. Or use the download icon on any row to save just that photo.
You asked for a bigger size than the original. Shrinking stays sharp. Growing cannot add detail that was never there.
Check the original size and stay under it. A very low quality setting does this too. Try 80%.
You saved as JPEG. JPEG cannot hold a clear background. Use PNG or WEBP instead.
Maintain Aspect Ratio was off and you typed both numbers. Turn it back on and type only the width.
Size and compression are two different controls. Heavy files need both.
Cut the width first. Then tick Compress Image and step the quality down. WEBP often saves another 25-35% over JPEG.
Everything runs on your own device. A few hundred large photos can use a lot of memory. Split the job into smaller batches.
Open the Bulk Image Resizer and drop your photos in. Something not working as described? Tell us.