java - Replace strings with incrementing value

Question

I have an ArrayList that is built from posts in a forum, each entry is a post. When I am building the entry I am replacing all elements with the string "Image[x]". After the array list is filled I want to go back and replace all instances of "[x]" with an incrementing integer.

I am building my array list using this code:

Elements wholePosts = doc.select("div.post_body");
            for (Element wholePost : wholePosts) {
            Elements texts = wholePost.select("div[itemprop=commentText]");
            for (Element text : texts) {

                String nobr = text.html().replaceAll("(?i)<br[^>]*>", "newlineplaceholder");
                String formatted1 = nobr.replaceAll("<img src=.*?>", "Image[x]");
                Document finalPost = Jsoup.parse(formatted1);
                String almostfinalText = finalPost.text();
                String finalText = almostfinalText.replace("newlineplaceholder", "\n");


                datumList.add(finalText);

            }

I have tried to replace the string and increment it in the above code but it only increments for each post element, so if there are multiple images in a post, post 1 would contain "Image1, Image1" and post 2 would contain "Image2, Image2". What I am looking for is for post 1 to contain "Image1, Image2" and post 2 to contain "Image3, Image4"