All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
What we understand from your question is that you do not buy the goods, neither from the wholesaler nor from the manufacturer; and you rather advertise its picture, and if you find somebody having the desire for it, you would sell it to him at the retail price, and buy it from the wholesaler at the wholesale price, with your profit being the difference between the two prices. However, that is forbidden under Sharee‘ah, because it is to sell what you do not have in your possession, and make profit of that which has not become your liability (i.e. you do not bear its risks and responsibility).
The Sharee’ah alternative to that is to act as a broker on behalf of the owner of the goods, be he its manufacturer or wholesaler; and it is permissible for you to ask for a commission for brokerage agreed upon with the seller or the buyer or both.
If you buy the goods from the manufacturer or the wholesaler for yourself, and then wish to sell it, you should first hold it in your possession, taking into consideration that the possession of anything differs according to the nature of that thing. Also, you have the right to appoint an agent to possess it on your behalf, even by keeping it in a separate place in the seller's warehouse distinct from his own; and if you find somebody who wishes to buy it, you could sell it to him by whatever price you both agree upon, and you could ship it to him, or let the seller do so if he committed himself to do it and provided this service.
Allaah Knows best.