I needed a photo’s manager application mainly in order to modify the size of a lot of pictures to be shown in a site. In fact, as you probably know, it is convenient to resize high definition pictures before uploading in a site, if you only want to see them on a PC screen: less uploading time, less storage needed, quicker view for the end-user visiting your site!
There are many possible applications doing photo management features for free (e.g. Image Tuner, ACDSee Free from ACDSee site). I choose XnView (XnView site) or better XnViewMP (actually ver. 0.69) because it allows lossless transformations (so without loosing in resolution, as very often it happens with other tools only after a landscape to portrait rotation!).
Here you can see the easy procedure to resize all or some photos in a directory with a bach process using XnView:
1) Select the folder (or all the photo if you want to apply the requested transformations to only some of them)
2) Select, from the menu, Tools -> Batch convert.
Choose, in the Output tab, the directory where the modified photo will be stored (e.g. C:\Temp).
Verify in Input tab the photos that will be processed and select, in the Actions tab, one or more actions to be applied to all the selected photos. In our case, if we want to resize them, so we can select Add action -> Image -> Resize and, for having a good resolution for web, choose the Preset 1024×768, leaving checked the Keep ratio checkbox. On your right you can see a Preview of the first photo Before and After the transformation. You could add, if needed, more than that one action, obviously …
3) Click the Convert button at the bottom right of that window and, after a while, you will find all the transformed photos in the output directory you selected (in the example: C:/Temp)
PS: you can see also the following tutorial or this video if you have some doubt how to proceed!