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For those that are wanting to learn (or those who have not been raised by the “digital age”), file size and other forms of digital measurements can be a bit confusing. I mean, what even is a GB? It’s not something physical right in front of you, so what is it? 


Back in the Flash Player era (God bless the 90’s) ad-serving platforms had a standard file size limit capped at 40KB. However, with the advent of HTML5 banners, the ad-server allowance has now expanded to 150KB-300KB, marking a substantial increase of 650%! 


But what exactly is file size, and how does it impact your digital banner ad campaign? Let’s delve into the fundamentals.


What Is File Size?

File size refers to the amount of space a file occupies on a storage medium, such as a computer hard drive or ad server. While commonly referred to as “file size” in the industry (or “filesize” for the audacious), it’s more accurately termed file weight—the heaviness of a file and the space it requires for storage.


Is File Size The Same As Pixel Size?

No, file size shouldn’t be confused with pixel size, which denotes the space an image occupies on your screen. File size is about how heavy a file is and the storage space it demands. For instance, an MPU banner ad may take up 300×250 pixels on your screen but can vary in file weight from a few dozen KB to several GB.


File Size Is Equal To The Number Of Pixels?

While pixel size affects file weight, it’s not a direct cause. A poorly constructed MPU with sloppy code and inadequate image compression could weigh over 3GB, despite a standard pixel size. Conversely, at The Banner Boys, we often craft visually appealing, fully animated DMPUs under 150KB in file weight.


What’s The Difference Between File Size And Pixel Size?

Think of aeroplane luggage: pixel size is akin to the luggage’s size, while file size is its weight. Even if the pixel size remains constant, a banner’s file weight can fluctuate based on the assets it incorporates.


Does Animation Impact File Weight?

The animation code itself has a light file weight, but the creative assets used in the online banner ad contribute the most. More assets in an animation mean a higher file weight.


File Size Categories

Common file sizes range from the smallest to the largest.


Storage Capacity & File Sizes:

  • 1 byte (B) = Single unit of space
  • 1 kilobyte (KB) = 1,000 bytes
  • 1 megabyte (MB) = 1,000 kilobytes
  • 1 gigabyte (GB) = 1,000 megabytes
  • 1 terabyte (TB) = 1,000 gigabytes
  • 1 petabyte (PB) = 1,000 terabytes


Why Should You Keep File Sizes Low? 

There are many reasons why it is optimum to keep file sizes as low as possible. Large file weights compromise viewability and website load time. Cumulative file weight from multiple ads on a page, especially near the limit, can slow down the website, affecting usability, how search engines view your page, and negatively impact the user experience which could result in a high number of users bouncing from your page. Publishers set file size limits to prevent this.


Google Says I Have A Limit Of 5mb, Do I Still Need To Stick To Old Limitations?

Google are seen (and rightfully so) as the fore front of ad space and publishing. However, website owners and publishers can set limitations to the file size of banner ads on their pages as not to negatively impact their user experience. Due to this, marketers are encouraged to remain within the 150kb-300kb range for any creative HTML5 assets.


But What Happens If A Banner Ad Is Above The File Limit? 

The worst-case scenario? Your animated ad won’t be seen. Ads exceeding the file size limit may be rejected, and a static JPEG image will be served instead.


It’s crucial to collaborate with experienced HTML5 banner developers like Banner Boys, specialising in HTML5 banners and digital display, who understand file weight’s importance for optimal visibility. 


What Increases File Size?

Factors like colours, gradients, and high-res images can increase file weight. Using CSS for colors and gradients, opting for graphics instead of pixel-based images, and employing proper compression settings can help combat these issues.


Can I Compress HTML5 Files? 

Yes, with the correct compression settings, good image quality and smaller file weight can be achieved. For photos, a compression level of 70-80% is generally acceptable without significant quality loss.


What Types Of Banner Is Best For File Size? 

For smaller file sizes, starting with an MPU banner, especially for mobile display units, is recommended. DMPUs or Billboards, being larger banners, may struggle to fit under file size limits.


What Are The Benefits Of Lower File Size? 

Smaller file weights result in faster website loading times, favouring search engine rankings and improving your ad’s visibility.


Are You Unsure Of What File Size You Need? 

Contact your media agency to determine the required file size for your digital banner ad campaign. If you seek assistance in creating outstanding digital display campaigns, reach out to Banner Boys at TBM today!

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