4 Simple Ways to Resize a Picture in KB

Are you working with an image that's too large or small? Whether you need to increase, decrease, or specify the exact number of kilobytes (KB) of an image, we have you covered! You'll just need to adjust the dimensions and file size. Here's how to change the size of an image in KB using your Windows or Mac computer and phone. While there isn’t a great app for setting an exact file size on Android or iPhone, you can use a web-based resizer like LunaPic in your phone’s browser.

Resizing Image File Sizes

To decrease the size of your image in KB, use a free online editor such as LunaPic. Just upload your photo, select a file size, and then save the new image. You can also use Paint on Windows or Preview on Mac to resize your image and reduce the file size.

Method 1

Method 1 of 5:

Using LunaPic (Browser)

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Go to lunapic.com/editor/ in your browser. LunaPic is a free, online photo editor with which you can increase or decrease an image's size by kilobyte.
2
Click Quick Upload . It's on the right below the image banner at the top of the page.
- You might not see this option if you’re using the mobile version of the website. Instead, tap Upload on the image banner at the top of the page, or tap Upload Options below the banner to go to a more advanced upload page.
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This grey button is in the middle of the page. Clicking it opens a file browser window.
Click the photo that you want to resize . Use the file browser window to locate a photo you want to resize. Then click it to select it. You may first have to select the photo's folder on the left side of the window.
It's in the bottom-right corner of the window. The photo will be uploaded to the LunaPic site.
This link is in the group of options above the photo.
7
Type a file size in KBs. Double-click the white file size text field above the folder to select its contents, then type the KB size you want the photo to be.
- If you need your file to be larger, you'll type in a number that's larger than the number currently listed here (and vice versa).
It's a grey button to the right of the kilobyte number field. Your photo will be resized, both in file size and in physical dimensions.
9
Click Save . It's below the image on the left side. This downloads the newly resized photo.
- You may have to scroll down to see Save .

Method 2

Method 2 of 5:

Using Preview (Mac)

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1
Open the Finder. It's the icon that resembles a blue and white smiley face. It's in the Dock at the bottom of the screen.
- You can choose an exact output file size in Preview, but only for certain image formats.
Navigate to the photo you want to resize . Use the Finder to open the folder containing the photo you want to resize. You can use the sidebar on the left to open common folders on your Mac.
3
Open the image you want to resize in Preview. Preview is the default image viewing app on Mac. You can normally open an image in Preview by double-clicking it. If Preview is not your default image viewer, use the following steps to open the image in Preview.
- Right-click on the image. If you are using a Magic Mouse or trackpad , click with two fingers. You can also Ctrl -click the image.
- Click File .
- Click Open With .
- Click Preview .
- You can also open Preview, then select File > Open and browse for your file.
4
Use the Export tool to set a specific file size. With certain image formats, you can set an exact file size in KB using Preview. If you simply want to resize your image and don’t need an exact size in KB, use the steps below . Here’s how to set an exact file size:
- Click File in the menu bar at the top of the screen, then select Export .
- Select one of the following formats using the Format dropdown menu: JPEG , JPEG-2000 , or HEIC .
- Use the slider at the bottom of the window to adjust the quality of the file. You’ll see the file size in small text at the very bottom of the window. Move the slider until the file is the size you want.
- Click Save .
It's in the menu bar at the top of the screen.
You'll find this in the Tools drop-down menu.
Use the drop-down menu next to the "Height" and "Width" boxes to select a percentage. The default unit is "Percentage". You can also select "pixels", "inches", "cm", and more.
8
Type a new number in the "Width" or "Height" boxes. You can use either one of these boxes to resize the image. If you selected "Percentage," type what percent you want the new image size to be. If you selected "pixels," "inches," or another unit, type however many units you want the new image size to be in the boxes.
- Ensure that the checkbox next to "Scale proportionally" is checked so that the image is not distorted when you resize it.
- Alternatively, you can click the drop-down menu next to "Fit into" and select an image size to quickly resize the image.
It's in the lower-right corner of the "Image Dimensions" window. This applies your changes to the photo.
It's in the menu bar in the upper-right corner.
11
Click Save . It's in the File drop-down menu. This will save your file on your computer using the dimensions that you selected.
- To save the image in a different format, click Export… in the File drop-down menu, then click the "Format" drop-down menu and select one of the following image formats:
  - JPEG - best for photos on the web. Compact files.
  - JPEG-2000 - high quality, good compression. Smaller files.
  - OpenEXR - best used to compress video files.
  - PNG - best for higher-quality graphics and photos. Larger files.
  - TIFF - best for editing and storing images. Larger files.

Method 3

Method 3 of 5:

Using Paint (Windows)

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1
Click the Windows Start menu . It's the button with the Windows logo in the bottom-left corner of the screen.
- With this method, you can't select a specific file size for your image, but you can adjust the image size to decrease the file.
Doing so searches your computer for the Paint program.
It's at the top of the Start window. This will open the Paint program.
4
Open your image in Paint. Use the following steps to open an image in Paint:
- Click File in the upper-left corner of the window
- Click Open to open a file browser.
- Click a photo you want to resize .
- Click Open in the lower-right corner of the file browser.
5

Click on Resize . It's the rectangular icon in the "Image" section of the toolbar at the top of the window. This will open the "Resize and Skew" dialog box.
6

Click the checkboxnext to "Maintain aspect ratio". It's at the bottom of the "Resize" box. This ensures that your photo doesn't get stretched or flattened when resizing it.
7
Set a new size for the image. Use one of the following options to resize the image.
- Check the Percentage box. Then type a number percentage in either the "Vertical" or "Horizontal" field.
- Check the Pixels box. Then type a specific pixel number (e.g., 800 x 600) in the "Vertical" or "Horizontal" field.
8

Click OK . It's in the bottom-right corner of the window. Your dimensions will be applied.
9
Save your file. Use the following steps to save the image:
- Click File in the upper-left corner.
- Click Save as in the pop-out menu.
- Type a name for the image in the "File name" text box.
- Click Save as type (optional)
- Select one of the following file types:
  - GIF - best for web graphics. Small files.
  - BMP - best for web graphics. Compact files.
  - JPEG - best for photos on the web. Compact files.
  - PNG - best for higher-quality graphics and photos. Larger files.
  - TIFF - best for editing and storing images. Larger files.
- Click Save .

Method 4

Method 4 of 5:

Using Android

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1
Download the free Photo & Picture Resizer app from the Google Play Store . This app won’t let you select an exact file size, but it will allow you to make your pictures bigger or smaller, which will also affect the size and quality of the file. Use the following steps to download the app:
- Open your Android's Google Play Store .
- Tap the search bar.
- Type in "photo & picture resizer".
- Tap Photo & Picture Resizer .
- Tap INSTALL .
- Tap ACCEPT .
- Wait for the app to install. ^{[1]
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2
Open Photo & Picture Resizer. Tap OPEN in the Google Play Store, or tap the Photo & Picture Resizer icon on your home screen.
- With this method, you can't select a specific file size for your image, but you can adjust the image size to decrease the file.
3
Tap Select Photos . This is the first option.
- Your gallery will open.
- You may need to allow permission for the app to access your photos.
4

Tap Resize . This is the icon at the bottom with the two arrows.
5
Select the dimensions. You can use the preset percentage to downsize your image or the width x height dimensions. If desired, you can tap Custom to enter your own specifications.
- If you enter your own custom dimensions, you can check the box to preserve the aspect ratio.
- If you don't need a specific size, you can scroll down to Resolution & File Size and select a preset. Keep in mind this gives you less control on how your image ends up looking.
6

Tap Ok . The image will begin resizing. Once it's finished, you can tap Share at the bottom to save it in your gallery, or tap See in resized photos to find it in the app's gallery.

Method 5

Method 5 of 5:

Using iPhone or iPad

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1
Download Image Size from the App Store. This is a free app that allows you to resize an image.
- With this method, you can't select a specific file size for your image, but you can adjust the image size to decrease the file.
2

Upload your image. Tap the photo icon in the top-left corner, and then select a photo from your Camera Roll. You may need to allow permission for the app to upload your photos.
3
Select the dimensions. At the top of the screen, you can select pixel , mm , cm , or inch . Once you select an option, enter the dimensions you want.
- If you're adjusting a square image, tap the lock icon between the width and height field to keep both inputs the same.
4

Save your image. To save the new photo to your device, tap the download icon at the bottom of the screen. You can also email or print the new photo.

Community Q&A

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Question

Which app can I use for this?

Community Answer

To decrease or increase size, decrease or increase the resolution of the image in a program like Photoshop or GIMP.

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Question

How can I reduce the size of a 2 MB image to 30 KB without compromising on the quality of the photo?

JLloyd

Community Answer

Unfortunately, what you're trying to do isn't possible (at least, not in this dimension!). Lowering an image's size inherently means that you're lowering the picture's quality.

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Question

Can I increase a 103kb size photo to 1mb to get it printed on an a canvas?

Community Answer

Increase the resolution in a program such as Photoshop or GIMP to make it fit.

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On Windows, your file may not initially appear to have a different file size after saving in Paint. Refreshing your screen a few times by pressing F5 will update the file's information.

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As a general rule, lowering a photo's dimensions (e.g., from 800 x 800 to 500 x 500) will decrease the photo's file size, while increasing the dimensions will increase the file size.

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Warnings

Resizing an image will always change the image's resolution and perceptible quality. You cannot resize an image without changing its quality.

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4 Simple Ways to Resize a Picture in KB

Resizing Image File Sizes

Steps

Using LunaPic (Browser)

Using Preview (Mac)

Using Paint (Windows)

Using Android

Using iPhone or iPad

Community Q&A

Video

Tips

Warnings

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