Big images make Construct slow?

I was making the stages by importing tile by tile, and then building the stage by copying tiles, but then I realized that I can build the stage in just 1 big image and then import it on Construct. Would that make Construct slow? Maybe 1 stage no, but imagine 20 ?

I know Construct have limits for the image size (4028 x I dont remember), but I can cut the images and then just paste 2 or 3 big tiles instead of a lot of small tiles.

Thank you again.

If you're reusing the same small tiles over and over again, you'll save a lot of VRAM, which is usually more important than how fast it is. If you can use tiled backgrounds for large areas of repeated tiles, it'll be fast anyway (especially if they are a power-of-two size).