Invalid URL for Logo Header

[RoadAndBridgeGISAdmin]

I'm trying to add logos to my header on Dashboards but I keep getting an "Invalid URL" message, I've tried multiple images. There is no place to upload an image. Has anyone else come across this and found a solution?

[JenniferAcunto]

I have found that Dashboard tends to only like image links that end in .jpg or .png.

Another option would be to upload the image to ArcGIS Online/Enterprise through My Content.

Share the image publicly (required) and use the URL in the bottom right corner of the item details page.

While this URL doesn't end in .jpg or .png, it seems that the item type of image helps Dashboard recognize it as an image. 

[Teresa_Blader]

I have an image that ends in png and dashboards still won't display it. And when added it clears out the title and subtitle.