The Tableau Performance Checklist: Rendering – Use Transparent Background PNGs

Data

The Tableau Performance Checklist: Rendering – Use Transparent Background PNGs

by Jon Bajon

The Tableau Performance Checklist series is designed to help you streamline your dashboard performance and Tableau Server configuration. Each post expands upon one item listed in the master Tableau Performance Checklist.

Who doesn’t love efficiency? We are finishing up with the rendering category today by returning to custom shapes. Let’s get started:

“If using custom shapes, use transparent background PNGs instead of JPGs. Views will render cleaner, and shape files will take up less space.”

Didn’t know we’d get into some Photoshop tips, eh?

Images & Custom Shapes

Generally, when creating symbol maps within Tableau, users select from prebuilt shape pallets. But once in a while, there is a need for custom images to make a graph stand out. It first makes sense to discuss the difference between PNGs and JPGs.

PNG stands for Portable Network Graphics. A PNG is a lossless compression image file, meaning that an image is made smaller without reducing the quality. PNGs are most commonly used for images with sharp contrasting colors, text or graphic lines. PNGs usually have a large file size.

JPG stands for Joint Photographic Experts Group. A JPG is a lossy compressed image file, meaning that an image is made smaller but with a reduced effect to the quality. JPGs are most commonly used for high quality photographs. Generally, JPG files have a smaller file size than PNGs

To illustrate the difference, check out these two photographs.

JPG:

JPG image

PNG:

PNG

From first glance, it is nearly impossible to tell the difference. The real difference comes in once you look at the properties and the sizing of the two files.

JPEG properties

PNG properties

For custom imaging in Tableau, PNG images have a massive advantage over JPGs because the PNG file type supports a transparent background, which reduces a lot of unnecessary file size. JPGs, however, do not support transparency. Let’s take a look at using a transparent PNG vs regular JPG file for a custom image.

InterWorks logo

Above is a PNG of the InterWorks logo. There is no white background. This image of the logo can overlay any other graphic seamlessly and still maintain a sharp, clear quality. This is possible by setting an alpha channel. An alpha is a degree of opacity of the pixel which can be altered to select various levels of transparency. This image is 33.7 Kb. The big reason for this is that all of the unnecessary white background has not been included. We covered in our previous article in the Tableau Performance Checklist that the smaller the image size, the better for both loading and exporting.

PNG is also favorable over the older GIF, which also supports transparency. This is because the edges on a PNG image are much cleaner than a GIF. Here are all three varieties on a different colored background to illustrate their differences:

IW JPG
IW PNG
IW GIF

The first image on the left is a JPG (no transparency), the second is our PNG, and the last is the GIF. Pretty big differences in terms of quality and file size.

Specifically, in Tableau we can see the different between using a transparent PNG image versus JPG.

JPG images in Tableau:

JPGs in Tableau

PNG images in Tableau:

PNGs in Tableau

The main difference is the lack of the white background due to transparency.

Mastering Best Practices

If you’re interested in becoming a Tableau Server guru, then learning these performance best practices is essential. Check back frequently as we add new posts and dive deeper into each point in the Tableau Performance Checklist.

Another great way to identify best practices is to leverage the insights offered by our Performance Analyzer, part of Workbook Tools for Tableau. It will examine all of your workbooks, worksheets, dashboards and data sources against a list of best practices to ensure that you’re using all the tips and tricks to guarantee your visualizations are moving at light speed.

As always, feel free to get in touch with us if you have any questions regarding performance or anything Tableau related! We’d be happy to help.

Contact Us!

Want More The Tableau Performance Checklist

  1. The Tableau Performance Checklist
  2. The Tableau Performance Checklist: Data – Keep Analysis Simple
  3. The Tableau Performance Checklist: Data – Bring in Only Needed Data
  4. The Tableau Performance Checklist: Data – Use ‘Describe’ to Explore
  5. The Tableau Performance Checklist: Data – Remove Unused Columns from Extracts
  6. The Tableau Performance Checklist: Data – Use One TDS File
  7. The Tableau Performance Checklist: Data – Use Extracts
  8. The Tableau Performance Checklist: Filtering – Minimize Quick Filters
  9. The Tableau Performance Checklist: Filtering – Avoid ‘Only Relevant Values’ in Quick Filters
  10. The Tableau Performance Checklist: Filtering – Avoid High-Cardinality Quick Filters
  11. The Tableau Performance Checklist: Filtering – Avoid Quick Filters That Drive Context Filters
  12. The Tableau Performance Checklist: Filtering – Keep Range Quick Filters Simple
  13. The Tableau Performance Checklist: Filtering – Use Dashboard Filter Actions
  14. The Tableau Performance Checklist: Filtering – Don’t Be Lazy with User Filters
  15. The Tableau Performance Checklist: Custom SQL – Limit in Live Connections
  16. The Tableau Performance Checklist: Custom SQL – Avoid Parameters
  17. The Tableau Performance Checklist: Custom SQL – Watch for Useless Clauses
  18. The Tableau Performance Checklist: Calculations – Use Calculated Fields Carefully
  19. The Tableau Performance Checklist: Calculations – Limit Blended Calculations
  20. The Tableau Performance Checklist: Calculations – Avoid Row-Level Calculations Involving Parameters
  21. The Tableau Performance Checklist: Rendering – Avoid High Mark Counts
  22. The Tableau Performance Checklist: Rendering – Limit Text Tables With Lots of Marks
  23. The Tableau Performance Checklist: Rendering – Minimize Image & Shape File Sizes
  24. The Tableau Performance Checklist: Rendering – Use Transparent Background PNGs
  25. The Tableau Performance Checklist: Local Computations – Server Performance
  26. The Tableau Performance Checklist: Local Computations – Table Calculations
  27. The Tableau Performance Checklist: Dashboard Layout – Limit Number of Worksheets
  28. The Tableau Performance Checklist: Dashboard Layout – Fix Dashboard Size

More About the Author

Jon Bajon

Analytics Consultant
Tableau Viz: How Much Heat Can You Handle? It might sound controversial, but a common practice in my family (and many families throughout Louisiana) was something called ...
Questions from Tableau Training: Can a Top N Parameter be Nested Within Other Fields? The latest question from Tableau Training comes from Ryan, who was in a DII: Intermediate course in New York City. “I know I can ...

See more from this author →

Subscribe to our newsletter

  • I understand that InterWorks will use the data provided for the purpose of communication and the administration my request. InterWorks will never disclose or sell any personal data except where required to do so by law. Finally, I understand that future communications related topics and events may be sent from InterWorks, but I can opt-out at any time.
  • This field is for validation purposes and should be left unchanged.

InterWorks uses cookies to allow us to better understand how the site is used. By continuing to use this site, you consent to this policy. Review Policy OK