This wikiHow teaches you how to change the kilobyte (KB) size of an image file. You can adjust the photo size (in kilobytes) directly using the free online editing program LunaPic. If you want to resize your photo by decreasing or increasing its dimensions, you can use free programs on Windows and Mac computers, as well as download and use free apps on your iPhone or Android device. However, keep in mind that decreasing the image size in kilobytes will also decrease the resolution. Meanwhile, increasing the file size does not necessarily increase the resolution. Instead, the results may appear blurry or pixelated.
Step
Method 1 of 5: Using LunaPic
Step 1. Open LunaPic
Visit https://www140.lunapic.com/editor/ in a browser. LunaPic is a free online photo editor that allows you to enlarge or reduce the image size in kilobytes.
Step 2. Click Quick Upload
It's at the bottom right of the page.
Step 3. Click Choose file
It's a gray button in the middle of the page. Once clicked, a file browser window will open.
Step 4. Click the photo you want to change
Click the photo you want to resize. Use the file browser to find the location of the photo file that you want to edit. Then, click to select it. You may need to select the photos folder on the left side of the file browsing window first.
Step 5. Click Open
It's in the lower-right corner of the window. The photo will then be uploaded to the LunaPic site.
Step 6. Click Set File Size
This link is in the selection group above the photo.
Step 7. Type the file size in KB
Double-click the white text field containing the file size above the folder to select its contents. Then, type in the file size you want to apply/apply.
If you want to increase the file size, type a number that is larger than the current displayed number (and vice versa)
Step 8. Click the Resize File button
It's a gray button to the right of the kilobyte number column. After that, the photo size will be changed, both file size and physical dimensions.
Step 9. Click Save
This link is in the lower-left corner of the page. After that, the program will start downloading the photo at its new size.
- Scroll down to find the button Save (save).
- You can also click "Facebook", "Imgur", "Pinterest", "Google Photos", or "Twitter" to share the image through one of these platforms.
Method 2 of 5: Via Windows
Step 1. Open the “Start” menu
Click the Windows logo in the lower-left corner of the screen.
Step 2. Type in paint
Thus, the computer will search for the Paint program.
Step 3. Click Paint
It's at the top of the "Start" window. After that, the Paint program will be opened.
Step 4. Open the desired image in the Paint program
Follow these steps to open an image in the Paint program:
- Click File (file) in the left corner of the window.
- Click Open (open) to open the file browser.
- Click the photo you want to resize.
- Click Open in the lower right corner of the file browser.
Step 5. Click Resize
The button with the square icon is in the " Image " section of the toolbar at the top of the program window. After that, the " Resize and Skew " dialog box will be opened.
Step 6. Click the checkbox
next to "Maintain aspect ratio".
This option is at the bottom of the " Resize " box. This ensures that the photo is not stretched or compressed when resized.
Step 7. Set a new size on the image
Select one of the following options to resize the image.
- Check the box " Percentage ” (percentage) to enter a percentage value in the " Vertical " or "Horizontal" column.
- Mark the box Pixels (pixels) to enter a specific pixel dimension (eg 800 x 600) in the " Vertical " or "Horizontal" fields.
Step 8. Click OK
It's in the lower-right corner of the window. Thus, the selected image size will be applied.
Step 9. Save the file
Follow these steps to save the file:
- Click File in the upper left corner.
- Click Save as (save as) in the pop-out menu.
- Type an image name in the " File name " field.
- Click Save as type (optional)
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Choose one of the following types:
- GIF - Best suited for web graphics. Small file size.
- BMP - Best suited for web graphics. Compact file.
- JPEG - Best suited for photos on the web. Compact file
- PNG - Best suited for graphic and small web files. Big size.
- TIFF - Best suited for editing and saving images. Large file.
- Click Save.
Method 3 of 5: Via Mac
Step 1. Open Finder
This app has a blue and white smiley face icon. It's in the Dock at the bottom of the screen.
Step 2. Find the photo you want to resize
Use the Finder to open the folder containing the photo you want to resize. You can use the menu on the left to open similar folders on a Mac.
Step 3. Open the image you want to change in Preview
Preview is the main image opening application on the Mac. Usually you can open an image in Preview by double-clicking it. If Preview is not the main image opening application on your computer, follow these steps to open images with Preview.
- Right-click the image. If you're using a Magic Mouse or trackpad, click with two fingers.
- Click File.
- Click Open With.
- Click Preview.app.
Step 4. Click Tools
It's in the menu bar at the top of the screen.
Step 5. Click Adjust Size…
This option is in the drop down menu Tools (equipment).
Step 6. Select the unit of measure
Use the dropdown menus next to " Height " and " Width " to select a percentage. The main unit is "Percentage". You can also select " pixels ", "cm", and many more.
Step 7. Type the new number in the " Width " or " Height " box
You can use any of these boxes to resize the image. If you select " Percentage ", just type the new percentage you want on the image. If you selected " pixels " or another unit, type what size you want the new image to be in the appropriate box.
- Make sure to check the box next to " Scale proportionally " so that your image is not distorted when resized.
- Alternatively, click the menu that opens next to " Fit into " and select an image size to change it quickly.
Step 8. Click OK
This button is in the lower right corner of the " Image Dimensions " window. Once this button is clicked, the changes will be applied to the image.
Step 9. Click File
It's in the menu bar in the upper-right corner.
Step 10. Click Save
This option is located in the File drop-down menu. After that, the image will be saved on your computer in the size you have chosen.
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To save the image in another format, click Exports… (export) on the menu File, then click the "Format" menu and select one of the following image formats:
- JPEG - best suited for photos on the web. Compact file.
- JPEG-2000 - High quality with good compression. Small file size.
- OpenEXR - best suited for compressing video files.
- PNG - best suited for graphic and small web files. Large file size.
- TIFF - best suited for editing and saving files. Large file size.
Method 4 of 5: Via iPhone
Step 1. For free Resize Image app from App Store
Follow these steps to download the Resize Image:
- Open the App Store.
- Tap Search (search).
- Tap the search field.
- Type in resize image.
- Tap Search on the keyboard.
- Scroll down on the "Resize Image" app.
- Tap GET (get) next to "Resize Image".
- Enter Touch ID, or tap Install and fill in your Apple ID when prompted.
- Wait for the application to finish installing.
Step 2. Open Resize Image
Tap OPEN in the App Store, or tap the Resize Image app icon on the home screen. This app has a photo icon of trees and clouds.
If you are asked to allow Resize Image to send notifications, tap Allow (allow) or Don't allow (don't allow).
Step 3. Tap the "Photos" icon (photos)
Look for it in the lower left corner of the screen.
Step 4. Tap Photo Library when prompted
A window with your phone photo will open.
Step 5. Tap the photo album
A list of photos in the phone album will open.
Step 6. Tap the photo
The main window of the Resize Image application will open.
Step 7. Tap on the gray image with the slider bar
This is the app's Settings icon. It's in the second button at the bottom of the screen, right next to the " Photos " icon. A window will appear in the center of the screen.
Step 8. Resize the image
Slide the " Width " or " Height " switch to the left to reduce the image size, or to the right to increase the image size.
- Make sure the "Keep aspect ratio" button remains green so that the image is still in proportion even though the size has been resized.
- You can also tap one of the " Standard Sizes " labels at the top of the window to quickly resize the image.
Step 9. Tap Resize
It's at the bottom of the window. Your photo will be resized.
If you're warned that resizing photos can crash the app, just tap on it Yes (yes).
Step 10. Tap the icon that resembles a diskette
Here's the "Save" option icon. This is the fourth button at the bottom of the screen.
Step 11. Tap the icon with sunflowers
The new sized photo will be saved to the iPhone's Camera Roll.
Step 12. Tap Ok
The window in the middle of the screen will close.
Method 5 of 5: Via Android
Step 1. Download the free Photo Resizer HD app from Google Play Store
Follow these steps to download the Photo Resizer application.
- open Google Play Store on Android.
- Tap the search bar.
- Type in photo resizer hd.
- Tap Photo Resizer HD.
- Tap INSTALL (install).
- Tap ACCEPT (accept).
- Wait for the application to finish installing.
Step 2. Open Photo Resizer HD
Tap OPEN on the Google Play Store, or tap the Photo Resizer HD icon on the home screen. This button has a blue icon pointed to by four arrows.
Step 3. Tap on Gallery
It's in the center of the screen. The Photo Gallery application will open.
Step 4. Tap the photo you want to resize
The Photo Resizer HD application will be opened.
Step 5. Tap the icon with the diagonal arrow
Here's the Resize option icon. This icon opens the image resize menu.
Step 6. Tap Custom
It's at the top of the menu.
You can also tap on one of the image sizes in the list to quickly change it
Step 7. Type the new image size number in the text field
One column of this text for horizontal size, and another column for vertical size. You can use both to resize the photo. For example, if the text field has the number "300", replace it with "150" to reduce the size by half. You can also change it to "600" to double the file size.
Check the box next to " Keep aspect ratio " to make sure the image size stays in proportion even if it's resized
Step 8. Tap OK
It's at the bottom of the menu. The changes will be applied to the photo.
Step 9. Tap the icon that resembles a diskette
It's in the upper-right corner of the screen. After that, the photo with the new size will be saved to the Android Photo Gallery.
Tips
- As a rule, lowering the photo size (for example from 800 x 800 to 500 x 500) will reduce the photo bytes, while increasing the photo size will increase the photo bytes.
- On Windows, your file may not initially display its new size after saving in Paint. Press F5 several times to refresh the screen and update the file information.
