article 37054

Measuring Time To Display For Image Visuals In Power BI With Performance Analyzer

Carrying on my series on troubleshooting Power BI performance problems with Performance Analyzer, another situation where a report may be slow even when the DAX queries it generates against the underlying semantic model are fast is when you have large images displayed in an Image visual. Let’s see an example.

I created a Power BI report consisting of a single image visual that displayed a 25MB photo:

I then published the report – and this is important because the behaviour I’m describing here will only be relevant to published report – then cleared the browser cache, started Performance Analyzer and viewed the page with the image visual on. I then stopped Performance Analyzer, exported the results and visualised them with my custom visual. Here’s what I saw:

The Image visual took just over 6 seconds to load and almost all of that time is related to the Visual Container Resource Load event. You can guess that this is the time taken to load the image from the name of the event; looking at what happens behind the scenes when the report renders using Chrome DevTools confirms this.

It’s important to understand that the Image visual won’t take this long to load every time the report is rendered – caching means that the image will only need to be downloaded once. Still it’s another reminder that having a large image or a lot of small images on a page can have an impact on report performance.