Images can be quite small on Tensorboard when the dataset has small dimensions.
Instead of awkwardly zooming the whole board with ctrl +, you can actually pass the maximum number of images per row to the grid constructor on PyTorch:
images, _ = batch
grid = torchvision.utils.make_grid(images, nrow=2)
writer.add_image("images", grid, 0)
The default setting puts 8 images per row (on the left in the picture). If the zoomed images (on the right) are now too large, you can still collapse the grid to a miniature by clicking on it.