I would recommend IrfanView.
It has extensive batch options (File > Batch Conversion). I've used IrfanView a lot in the past for batch resizing of images, for which it seemed pretty efficient and easy to use. You can select a few simple operations from a list for the batch/conversion process. Adding watermark-texts is one of them.
This tutorial explains ...
Take a look at Daminion (I work at Daminion Software). This is a photo management software that you can use to watermark your images. Daminion Free version allows you to work with 15,000 images that can be imported per one local catalog.
How it works:
Import your photos to Daminion.
Select images that you want to stamp by your watermark.
Configure an ...
You could do this with the ImageMagick convert command from a batch file it will allow you to apply text to a file, convert the type, rescale, etc., all in a single operation - it is also free.
e.g. convert rose.jpg -draw "text 25,60 'By Any Other Name'" outdir/rose.jpg
Alternatively you could use python, PIL (the python image library) or Pillow (a fork ...
Xnconvert is small, portable and fast for those tasks
XnConvert is a powerful and free cross-platform batch image processor, allowing you to combine over 80 actions. Compatible with 500 formats.
When you open XNconvert, drag&drop all your pictures into Input
Under actions, select Add action » Image » Watermark
Choose your watermark file, opacity, ...
I found a Dysprosium Software Suite here. They call it "Watermark" hence, I edited my post.
It puts photographs and texts with adjustable size and directions in different place.
and one test result
I could use it to convert my pictures to PDF too.
ImageMagik gives you a command line, (or batch file), able to do exactly this sort of operation. This section of the documentation gives some of the many options to watermark images with either text, images or images generated from text.
The python MoviePy tool, (which installs and uses FFMPEG and needs ImageMagick installed for text operations), can be used to create a colour mask clip based on a specified colour, using mask_color and you can then use it to apply a watermark similar to the masked credits example, (https://youtu.be/NsTgBah6Ebk for the results), but with more transparency.
FormatFactory will allow you to add watermark to a video. It's free to download and use and it's actually quite good as it can do a lot of conversions on music, video and image files among others.
For watermark, it will accept any jpg,bmp or png image files.
The PDFtk PDF toolkit has, amongst many other features, adding watermarks, there are free and cheap versions both of which offer watermarks, it is cross platform and there is a command line interface so you can add the same watermark to multiple files in a single operation or you can use a batch script to add your standard watermark on demand.
Note that ...