Resizing images is a common task for many purposes, whether it’s to reduce file size for web use, change dimensions for printing, or scale up or down for specific needs. With the right tools and techniques, you can easily adjust image dimensions without sacrificing quality.
Why would you want to resize an image?
There are several reasons you may want to resize an image:
- To reduce file size for web use – Large images can slow down load times for web pages. Resizing to smaller dimensions can dramatically reduce file size.
- To change dimensions for printing – You may need to resize photos to specific dimensions for printing purposes, such as 4×6 or 8×10.
- To scale up for large-format printing – Upscaling a low-resolution image allows printing a large poster or banner.
- To scale down for mobile use – Resizing images to lower resolutions optimizes them for mobile screens.
- To crop for specific compositions – Cropping images to different aspect ratios like square allows for more design options.
- To change orientation from landscape to portrait (or vice versa).
- To alter the ppi (pixels per inch) to match printing requirements.
- To create thumbnails – Generating smaller thumbnail images to showcase galleries.
The key when resizing images is maintaining the proper resolution and quality so images don’t become pixelated, blurry or distorted. Using the right techniques and software will ensure high quality results.
What you need to know before resizing images
When working with digital images, there are two key factors that determine resolution and quality:
- Dimensions – This refers to the pixel width and height of an image. Resizing changes the overall dimensions.
- PPI – Pixels per inch. This measures the density of pixels in an image. Higher ppi means higher resolution quality.
Resizing images improperly can reduce image quality. Here are some key tips:
- When reducing image dimensions, choose a maximum resize that won’t drop below 100-150 ppi to avoid pixelation.
- When enlarging images, upscale by no more than 120% to avoid excessive interpolation.
- Use bicubic interpolation rather than nearest neighbor when resizing for smoother results.
- Avoid excessive compressing which can introduce artifacts and banding.
- For print, aim for 200-300 ppi at desired print size for best results.
Following these guidelines will help maintain optimal quality when resizing images to new dimensions.
How to resize an image using online tools
The easiest way to resize images is using free online tools. There are many web apps that make it quick and simple.
Here are some of the best online image resizers:
- IloveIMG – Resize jpeg, png, webp, and gif files. Change dimensions by pixels, percentage, or define max width/height.
- PicResize – Simple interface for resizing all major image types. Set custom width, height, or percentage.
- ResizeImage – Supports batch resizing multiple images at once. Provides responsive presets.
- Compressor.io – Resize while optimizing compression. Offers exact sizing presets.
- Simple Image Resizer – Minimalist resizer retaining EXIF data. Change width, height, or percentage.
To resize an image using online resizers:
- Go to the website and upload your image file.
- Enter new pixel dimensions in width and height fields, or use percentage dropdown.
- Adjust additional options like file format, quality, etc.
- Click the “Resize” button to process new version.
- Download the resized image to your computer.
That’s it! The online tool does all the work and delivers an optimized resized image with minimal effort.
How to resize an image using desktop software
For batch resizing, fine-tuned control, and professional results, a desktop imaging program is best. Here are the top applications for resizing photos and images on your computer:
Adobe Photoshop
The industry standard for photo editing allows precise resizing in several ways:
- Image > Image Size – Manually change pixel dimensions or resolution.
- Edit > Transform – Scale by dragging handles or entering percentage.
- Automate > Batch – Batch process multiple images.
GIMP
GIMP is a free open-source alternative to Photoshop with powerful resizing capabilities:
- Image > Scale Image – Enter pixel dimensions or percentage scale.
- Image > Print Size – Set resolution and dimensions for printing.
- Tools > Transform Tools – Interactive scaling and cropping.
Affinity Photo
This professional Photoshop alternative excels at image resizing:
- Layer > Resize – Specify dimensions in pixels, inches, cm, etc.
- Export Persona – Output resized files in multiple formats.
- Live Resize – Interactively scale layers using handles.
CorelDRAW
Popular graphics software with flexible image resizing tools:
- Arrange > Resize – Change dimensions by percentage or pixel size.
- Effects > Resize – Precisely scale objects and images.
- Export for Web – Batch export web-ready files.
For most projects, Photoshop, GIMP, or Affinity will have all the controls needed for professional image resizing and optimization.
How to maintain image quality when resizing
When altering image dimensions, you’ll want to minimize any reduction in visual quality. Follow these tips for optimal resize results:
1. Preserve original image
Always resize a copy of the original file instead of overwriting it. This protects the maximum quality version.
2. Downsize in increments
Gradually reduce dimensions in stages instead of extreme one-step resizing. Multiple incremental steps preserve details better.
3. Resize by percentages
Reduce image dimensions by percentages instead of arbitrary pixels values for more consistent results.
4. Use bicubic interpolation
Bicubic produces smoother resizing over basic nearest neighbor interpolation.
5. Don’t enlarge more than 120%
When enlarging images, upscale by no more than 120% to avoid excessive interpolation artifacts.
6. Add sharpening
After resizing, use sharpening tools to refocus fuzzy details.
7. Limit compression
Avoid heavy JPEG compression when resizing, which can introduce banding and artifacts.
8. Retain EXIF data
Choose resize tools that preserve EXIF metadata like date, camera settings, etc.
9. Resize in one direction
When possible, scale images on one axis only (width OR height) to maximize quality.
Following these best practices will help retain the highest image quality when resizing to new dimensions.
How to resize images for print
Preparing images for print has a few specific requirements to ensure optimal reproduction:
Target appropriate PPI
- 300 PPI for high-quality printing
- 200 PPI for standard prints
- 150 PPI minimum for acceptable quality
Determine print dimensions
- Resize images to match expected print size.
- Common print sizes: 5×7, 8×10, 11×14 inches, etc.
Set proper resolution
- Higher resolution equals better print quality.
- But excessively high resolution wastes resources.
- Keep res between 200-300 PPI at desired print size.
Resize in one direction only
- Avoid resizing width AND height together.
- Resize on single axis only for best quality.
Use bicubic interpolation
- Bicubic produces superior resizing over nearest neighbor.
- Smoother gradients, fewer artifacts and jagged edges.
Sharpen images
- Resizing often softens image details.
- Apply sharpening filter to improve edge definition.
- But don’t over-sharpen which causes artifacts.
Save as TIFF or PNG
- Avoid JPEG compression which degrades quality.
- TIFF or PNG retain all image data for printing.
Following this workflow will deliver print-ready images optimized for resolution, sharpness and reproducible quality.
How to batch resize multiple images
For resizing hundreds or thousands of files, batch processing is a necessity. Here are some batch resize options:
Photoshop
- File > Automate > Batch
- Record resize actions first, then apply to folders
- Output can be uncompressed TIFF or PNG
Lightroom
- Select images and use Export with presets
- Resize to exact dimensions in pixels
- JPG quality slider for optimized compression
GIMP
- Tools > Batch Process
- Record actions to play on multiple files
- Script-Fu extends batch capabilities
Affinity Photo
- Develop Persona presets enable batch editing
- Export Persona for batch export
- Export presets for quick bulk output
FastStone Image Resizer
- Dedicated batch resize tool
- Supports folder recursion, renaming, filters
- Quickly convert, resize, rename thousands of images
For the best results, record a photoshop action or create export presets that include the ideal resize parameters, formats and compression options.
How to resize wordpress images
For optimizing images used in WordPress sites, themes, and pages, there are several techniques:
1. Use featured image settings
- When uploading the featured image, set width and height.
- Crops image to proportions that works with theme layout.
2. Insert images using media library
- Upload and resize images to optimal dimensions first.
- Insert into pages and posts using media library.
3. Install a resizing plugin
- Plugins like Imsanity automatically resize on upload.
- Resize images on the fly as they are requested.
- Can also compress JPG quality to optimize filesize.
4. Use PNG format for graphics
- PNG is better than JPG for logos, illustrations, charts.
- Use tinyPNG to optimize PNGs by compressing up to 80%
5. Serve scaled images
- Use srcset and sizes attributes for responsive images.
- Browser only loads image size needed for device.
Properly resized and optimized images improve WordPress site performance.
Image resize mistakes to avoid
While resizing images is usually straightforward, there are some common mistakes that can sabotage image quality:
Excessive one-step resizing
Don’t severely scale down images in one dramatic resize. Do it gradually in multiple passes for better results.
Enlarging too much
When upscaling images, don’t increase size more than 120% to avoid excessive interpolation and artifacts.
Compression artifacts
Don’t save resized JPGs with high compression levels, which introduces banding and visual noise.
Pixelated images
Be aware of minimum PPI requirements based on viewing method. Don’t size for print then view on high-res device.
Over-sharpening
Use sharpening after resizing to improve edge definition. But excessive sharpening causes harsh artifacts.
No bicubic interpolation
Don’t use nearest neighbor method, which produces jagged pixelated edges. Always go with bicubic or better.
Metadata loss
Many tools strip out EXIF and other metadata during processing. Use ones that preserve metadata.
Avoiding these common mistakes will ensure high-quality results when resizing your images.
Frequently Asked Questions
Should images be resized for web?
Yes, resizing images before web use optimizes them by reducing filesize. For web, target a maximum width of 1500-1600px at 72 PPI. Resize and compress JPGs to 100-85% quality.
How can I resize images in bulk?
To resize hundreds of images quickly, use Photoshop actions, Lightroom export presets, GIMP batch processing, or dedicated tools like FastStone. Automating the process is easiest for large numbers of images.
What image format is best for printing?
TIFF and PNG are the best lossless formats for printing. Both retain full image data. Avoid JPG, which discards data and degrades quality when compressed.
Should I resize by scaling width or height?
For best results, resize images by adjusting width or height only, not both at once. This avoids distortion and improves image quality.
How do I know the right image size for my WordPress site?
Choose image dimensions optimized for your particular WordPress theme’s layout. Determine the maximum width needed for columns, galleries and insertion points. Scale images to those widths.
Conclusion
Resizing images while maintaining quality requires following best practices – work in increments, utilize proper interpolation algorithms, avoid extremes, sharpen carefully. Employing the techniques covered here will help you achieve great resize results for any purpose or project need. With the right tools and knowledge, you’ll be able to resize images professionally.