I have a question, is possible to post a for exemple a photo of a fluo tube and on the same space the same tube installed on a fixture or i need to make two independent uploads?

I combine both images in Adobe Photoshop and make one post in the gallery. I find it is neater because both images are intimately related. I do know some members here use other methods to combine images, however I cannot really help there because I only use Photoshop. So the short answer to your question is yes.

I usually use Photoshop to combine several images into one file and upload that way for closely related pictures. It also makes replying to comments easier as there's only one comment thread.

Some other ways include GIMP...the free/open source alternative to Photoshop, or one of the many collage maker phone/web apps that are available.

There's also a way to embed secondary files into a gallery post using the img and url tags. You upload the secondary pictures to either a external image host or to a private album and embed the images.

We've had quite good results from using Libre Office Draw... 

Thanks i Will use some software like this, and cool lamp

Thanks, there a few more on my gallery of oily lampses.