Creating appropriate text alternatives to render images accessible in the web is a shared responsibility among all actors involved in the web development cycle, including web localization professionals. However, they often lack the knowledge needed to correctly transfer image accessibility across different website language versions. In this paper, we provide insight into translators' performance as regards their accessibility achievements during text alternatives adaptation from English into French. While our work does not yet return conclusive results, preliminary findings suggest that the combination of both specialized and general web accessibility evaluation tools can help web localizers bridge the knowledge gap and potentially produce text alternatives of higher quality.