Hi Jorge,
Thank you for using Syncfusion products.
When we set image for ToolStripEx, image will be visible when the ToolStripEx is in Collapsed state.
From you Screenshots we suspect that you are trying to change the image size of ToolStripButton. But we could not set image size for ToolStripButton.
We can display the ToolStripButton with its original image size by setting ImageScaling property as None. Otherwise Image will be set in to default size (16 *16).
We have prepared the sample for the same. You can download the sample from the below location.
Sample:132228Sample
If we misunderstood your query please update us more details about your requirement. It will be help us to proceed further on this.
Regards,
Priyanga B