(Image source: realjock.com) Shares of Gap Inc. (NYSE:GPS) are advancing in the early session of trading after the retailer posted same-store sales for April that topped estimates. Gap reported an increase in same-store sales of 9 percent for the month April. The consensus street estimate was same-store growth of 0.1 percent for April. In addition, the retailer also increased its projected first quarter earnings above analysts’ expectations. Among the company’s varies brands, Old Navy saw the highest increase in sales.