Based on your question, "you upload any image and identify it".
1) For this, first you have to store (or save) many sample images (like apple, melon....) with proper texts (name of the object on the image for example) in your app.
2) Store the images in a defined size (256 x 256, or 512 x 512). This makes it easy and consistant.
3) Upload your image (target image) with the the same size described above (256 x 256 or 512 x 512).We are keeping consistancy.
4) If your image to be uploaded is larger than the defined size above, resample it and make it the same size as the sample images in your system.
5) Keep both sample and target images in the same image format (e. g., Format24bppRgb). This is a format consistancy.
6) Make image CORRELATION and calculate the correlation coefficinets between the Sample Images (again this is not image but images, because you have many sample images in your system) and the target image. Now, you got many correlation coefficients, select the highest one and corresponding image and text. Then, show up the text or do your search with your completed search functionlity.
You may use third party for image correlation job. This may help you: http://www.artuxsoft.com/image_math.aspx