Specific INFO for just about any device you are likely to be using;;
IPhones
To resize a picture on an iPhone, you can use the Photos app or the Shortcuts app.
Using the Photos app
- Open the Photos app
- Select the image you want to resize
- Tap Edit in the top right corner
- Tap the Crop icon
- Choose Original, Freeform, or Square
- Tap Done to save your changes
Using the Shortcuts app
- Open the Shortcuts app
- Create a new shortcut
- Add the “Resize Image” action
- Set your dimensions
- Run the shortcut
You can also download apps from the App Store to resize images on your iPhone.
Android Phones
To resize a photo on an Android device, you can use the Gallery app or a photo editing app.
Using the Gallery app
- Open the photo you want to resize in the Gallery app
- Tap the Edit button, which looks like a pencil
- Tap More Options (the three vertical dots) at the top right corner
- Select Resize
- Choose the resizing option you want
- Tap Save to apply the changes
Windows Computers:
You can resize pictures on a Windows computer using the Photos app, Microsoft Paint, or the Image Resizer Powertoy.
Photos app
- Open the image you want to resize
- Click the three dots in the top right corner
- Select Resize
- Choose a size option or set custom dimensions
- Click Save resized copy
Microsoft Paint
- Open Paint
- Click File then Open
- Select Resize in the Image section
- Enter the new size
- Click OK
- Save the image
Image Resizer Powertoy
- Install the Image Resizer Powertoy extension
- Right-click on one or more selected image files in File Explorer
- Select Resize pictures from the menu
- Choose the size that you want
You can also use the compression options in Microsoft Picture Manager to reduce both file size and picture dimensions.
I also use
Linux Ubuntu, mostly GIMP, but also have a batch tool, but doubt if anybody needs to know how with that.