It can be useful to resize a jpeg file, for example if you attach a series of images to an email or upload them to a website. If you resize an image, the quality will deteriorate a bit, and if you make an image larger than the original, blocks will always appear in the image. You can resize using free websites, the free image editing program on your computer, or with a free app on your mobile device.
Method 1 of 5: Using a website to adjust the image
Step 1. Go to a website that allows you to resize images
There are a lot of sites where you can quickly upload and resize any image, including jpegs. Search for 'resize jpeg' to see the different options. Resizing on a website works best on a computer, not a mobile device. Popular websites include:
Step 2. Upload the jpeg file you want to resize
Most websites allow you to upload all kinds of image files imaginable. Click the 'Choose file', 'Upload image', or 'Browse' button to find the image file you want to resize on your computer.
If the image you want to resize is on another website, you will need to download the image to your computer before uploading to the resizing website
Step 3. Use the Resize controls to set the size of the image
Every website does this in its own way. Perhaps you can drag the file into a field or use sliders to set the final size. It may also be possible to enter the exact dimensions.
If you make an image larger than the original, you have to take into account a significantly lower quality
Step 4. Select the compression (if you can)
Some websites allow you to specify a compression level. Higher compression results in a smaller file size, but also decreases the quality of the image. Look for a quality slider or drop-down menu to set the final quality. You can't set the quality on every website.
Step 5. Download the modified image
Once you've set the size and quality, you can resize and download the image. Click the 'Edit' button to load the new image. You will probably see a preview now before the image file is downloaded to your computer.
When downloading a modified image, be careful not to overwrite the original. Then you can always go back and try again if you're not happy with the result
Method 2 of 5: Using Paint in Windows
Step 1. Copy the image file
Before resizing the image in Paint, make a copy of the file so you don't lose the original. This way you can repeat the process later if you are not satisfied with the result.
To make a copy of the image file, right click on it and choose 'Copy'. Right click on an empty part of the same folder and select 'Paste to make a copy
Step 2. Open the image in Paint
Paint is a free image editor that comes with every version of Windows. Right click on the image file and choose Edit to open it in Paint.
Step 3. Select the whole image
If you want to resize the whole image, you have to select the whole thing by pressing Ctrl+A. You can also click the 'Select' button on the home tab and then choose 'Select all'. You will now see a dotted line around the image.
Step 4. Click on the 'Resize' button
You can find it on the home tab or you can press Ctrl+W. This will open the 'Adjust and resize' screen.
Step 5. Use the 'Resize' fields to resize the image
You can adjust the size by percentage or by pixels. If you choose 'Pixels', you can enter the exact size you want for the image. You can also enter percentages greater than '100' to make the image larger than the original.
- Paint keeps the original aspect ratio by default, and entering a value in one field automatically changes the value of the other field. This prevents the image from being stretched or squeezed during resizing. You can uncheck the box 'Keeps aspect ratio' if you want to be able to set the horizontal and vertical fields yourself.
- If you make an image larger than the original, the result will be a blocky image.
Step 6. Click 'OK' to see the resized image
As soon as you click on 'OK' your image will be adjusted based on the entered values. There is no preview available, so you need to make the changes to see the result.
If you're not happy with the result, press Ctrl+Z to undo the changes. You can also click the 'Undo' button at the very top of the screen
Step 7. Drag the edges of the canvas to the edges of the custom image
Your image has been resized, but the canvas is still at its original size. Click and drag the boxes around the edges of the canvas to adjust those as well and get rid of unnecessary white borders.
Step 8. Save your custom image
Once you're happy with the new format, you can save your changes to the file. Choose 'Save As' from the 'File' tab and choose 'JPEG Image'. You can then name the file and choose where to save it.
Method 3 of 5: Using Preview in Mac OS X
Step 1. Make a copy of your image file first
It's always a good idea to back up your original image before resizing. This way, if something goes wrong or if you don't like the end result, you can go back to the original. Select the image file, press ⌘ Command+C, then ⌘ Command+V to make a copy in the same place.
Step 2. Open the image file in the 'Preview' program
Usually it will open as soon as you double click on the file. If the image opens elsewhere, you can right-click on the file, choose 'Open with', then 'Preview'.
Step 3. Click on the 'Tools' menu and select 'Resize'
This will open a new screen where you can adjust the size.
Step 4. Click on the drop down menu to select the units you want to use
You can choose 'Pixels', 'Percentage' and a number of other units with which you can scale the image. By choosing 'Pixels' you can enter the exact dimensions of a custom image.
Step 5. Enter the length and width you want to use for the image
The two fields are linked, and a change in one therefore also adjusts the other, so that the proportions remain correct. This prevents stretching or compression of the image. If you want to be able to adjust both fields freely, you have to uncheck the 'Scale proportional' box to unlink.
Step 6. See what the new format will be
Before you make the changes, you can see what the new size of the image will be at the bottom of the screen. This is useful if you are resizing to meet the file size limits of email or other online services.
Step 7. Click OK to apply the changes
The image will be resized based on the settings you entered. If you're not happy with the result, press ⌘ Command+Z to undo the changes and go back to the original.
Step 8. Save your file
If you're happy with the new size, you can save the change to the file. Click on the 'File' menu and select 'Save' to save the changes.
Method 4 of 5: Using an iPhone, iPad, or iPod Touch
Step 1. Install an app that allows you to resize images
There is no built-in way on iOS devices to resize, but there are a multitude of apps available that can do that job for you. You can download these apps from the App Store on your iOS device:
- Resize It
- Image Resizer+
Step 2. Open the app and select the photo you want to resize
You will probably be asked to give the app access to your photos. This is necessary for the app to browse the photos on your device. Find the photo you want to adjust and tap it to open it.
Step #3. Tap on the 'Resize' button
Most apps have several tools to choose from, including resizing. Tap the 'Resize' button to resize the image.
Step 4. Enter a new size for the image
Each app has its own interface, but usually you can choose from a range of formats or you can specify your own format. The length and width are linked so that the proportions remain intact.
If you don't mind the image being stretched or squeezed, you can tap the chain link or padlock to enter different values in each field
Step 5. Save the modified file to the camera roll
Once the image has been adjusted, tap the 'Save' button to save it to the camera roll. You'll find it, like any other image on your iOS device, in the Photos app.
Method 5 of 5: Using an Android device
Step 1. Download an app that allows you to resize images
Android devices can't adjust images by default, but there are tons of apps out there that can do that for you. You can find these (mostly free) apps in the Google Play Store. Popular apps are:
- Photo & Picture Resizer
- Resize Me!
- Image Shrink
- Reduce Photo Size
Step 2. Open the downloaded app and give it access to your photos
When you launch the app for the first time, you may be asked to allow the app to access your saved photos. This is necessary for the app to load photos from the device.
Step 3. Open the photo you want to resize
Navigate with the app to the photo you want to resize. This process varies by app, but usually you'll need to click the "Select Photo" button in the main menu of the app to access the photos stored on your device.
Step 4. Select the resizing tool
After opening the image, you should probably tap the Resize tool. Again, the process may differ depending on the app you are using.
Step 5. Select the format you want to use for the image
You will see the original size in both pixels and file size. Depending on the app, you can choose from predetermined sizes or specify your own dimensions. If you enter a size yourself, the corresponding value will change with it.
Step 6. Save your images with the new dimensions
Depending on the app, the image will be saved automatically or you may have to manually tap the 'Save' button. The original file is not modified.
Step 7. Find back the modified images
Each app stores the modified images in a different place. In general, you can easily find images by opening the 'Pictures' folder and then searching for a folder named after the app. You can then share the images just like you would any other image on your device.