How do I resize photos and images in Omni?

Should you resize your pictures? If you have a full resolution photo or graphic then the answer is probably yes. Your images shouldn’t be wider than your page width (1100px max for a one column, 800 px for two column, 550 px for three column). Aim for a file size of around 300KB or less per image.


On this page


Check the file size

How can you find the file size and dimensions of an image?


  • Right click and select Get Info
    (this works in the images directory)


  • Right click, select Properties and click on the details section


Can I just make large images look smaller?


You might be tempted to scale down an oversized image in WordPress or Omni by adjusting the width and height values (or by clicking and dragging to make it smaller).

Don’t do that – resize your pictures before you upload them.

Just making an image look smaller on a page does not make the file size smaller. For example, if you upload a 5MB picture with dimensions 2000×2000 px, changing the dimensions to 100x100px on the page will only change the display of that 5MB image in the browser. Large files increase page load time and users with slow internet connections may leave your page before it even finishes loading. In the case noted here, it would be better to scale down your picture to 100x100px in a photo editor like Pixlr and upload it to your website. The file size will be much smaller and your page will load faster without a large image file slowing it down.

If you come across a slow or unresponsive web page, it’s often because someone uploaded a huge file. We have seen users upload image files as large as 34MB! Don’t do that! Keep your file size low and in kilobytes (KB) not megabytes.


How to resize your photos in Pixlr

Pixlr is a free image editing website.

Go to the Pixlr editor site 
(This is the beta version of the photo editor, but it does not require Flash like the previous version)

Click Open Image

Select an image from your computer and click Open.


Loading an image hosted online

If your picture is hosted on another website, you can click load URL to import your image. Just enter the image URL and click load.


Opening multiple images

If you already have an image open, when opening a new image, it will ask if you want to create new or add current. Unless you are familiar with layers in Pixlr, select create new for each image your wish to edit.


Opening an ultra high-resolution image


If the image you are loading into Pixlr is too big (over 3000px wide), it will require you to reduce the image size on import to edit it. If it does this, choose an image setting that will give you enough resolution to resize the image. In many cases, the web setting will be sufficient.


Image Resources

For this tutorial we are uploading a picture we found on the Vanderbilt Flickr stream.
(Images in the Vanderbilt Flickr feed are free for use by official Vanderbilt departments and organizations.)  For more image resources, check out the resources for photos, graphics and logos page.


New construction of dorms with Fall colors (Vanderbilt University / Steve Green)

  • Image Details

  • File Size: 3.8MB

  • Dimensions: 1600 x 1067


Resize your Image

Click on Image > Image size…

Enter the width and height values and click apply. Make sure constrain proportions is enabled so it will scale evenly.

Go to File > Save to save your image


File save settings


Below are some guidelines for filename, file type, quality settings, width, height and file size.

Filename: Choose what you would like the file to be called. Do not use spaces or special characters

File type:

  • PNG is a lossless file type and saves the full image resolution. Photographs saved in this format will generally have a much larger file size than JPEG.

  • JPEG is a lossy file type that compresses the image to reduce file size. Compressing a picture too much will make it look blurry or pixelated.

Image width: For recommended image sizes, see the General Image Sizing Guidelines. Under 1100px is usually good.

Quality: Reducing this value decreases the file size, but can also reduce detail


File size:

  • The file size is shown underneath the quality buttons

  • Reduce the quality enough to get the file size under 300kb without a visible loss to image quality. The setting should be in the kilobytes (KB) not megabytes (MB).


To download the image, click the Download button

Details about the downloaded image

  • Compressions: 20% (Quality: 80% in Pixlr)

  • File size: 154KB

  • Dimensions: 800 x 534px


A note about image compression

Lowering the quality by 10-20% (Med and High settings) can slim down the file size, but don’t overdo it. Compressing an image too much can make it look grainy.

For an extreme example, this is what the image looks like when the quality setting is set to 1%
(99% compression)

Image details

  • Compression: 99% (Quality 1% in Pixlr)

  • Size: 9KB

  • It’s only 9KB but image quality has been deteriorated so much that it can’t be used.


Enlarging small photos

Sometimes an image will be too small to be usable.

Large images can be made smaller








Smaller images can’t be enlarged to increase detail



  • Just changing the dimensions to resize your images in Omni or WordPress only adjusts the size in the browser and does not reduce the file size.

  • Resize your images in a photo editor like Pixlr before uploading them to Omni or WordPress

  • You can make big photos smaller, but you can’t make small photos larger . Enlarging a small photo will look pixilated or grainy because it doesn’t have enough resolution.

  • Keep your image file sizes small (300KB or less) so they will load quickly for site visitors.



General Image Sizing Guidelines

These are image widths that work with the following page column layouts.

  • One Column Page: Width: 1100px

  • Two Column Page: Width: 800px

  • Three Column Page: Width: 550px

The width is suggested instead of the height because you don’t want your images to be wider than the width of your total page width. Most Vanderbilt websites are 1100 pixels wide total, but the content area is smaller for two and three column pages. These image guidelines will help you stay within the width of your page layout to account for page margins and padding. You also wouldn’t want a really tall image either that pushes down the rest of your content.


Slideshow Image Sizes

  • Slideshow Setting Image Sizes

  • Edge to edge: 2600 x 500

  • Full width: 1100 x 400

  • Standard: 800 x 400

  • Mini: 550 x 300



About file size

Keeping your file sizes low (300KB or less) makes your pages download friendly to your site visitors with slow internet connections. Images displayed on your pages are automatically downloaded by site visitors. Large images (1MB and higher) can take a long time to load and your site visitors might leave before they even see your page. Large image files also create a lot of unnecessary strain on server resources.