…above! 
…online but takes other formats of image! (Maxi x 4, 500 images /month)
http://bigjpg.com
My try 
Original size for an old ZBrush Chalenge ! Texture 47 (?) Became my avatar!
x 4 with an very old prog!
x 4 without noise reduction
x4 with maximum noise reduction
Attachments
Interesting. It uses the reasonably old Waifu2x algorithm:
I recently tried this similar new service:
But I still prefer good old Photozoom Pro for high-quality bitmap enlargements:
appleseed is an open source, physically-based global illumination rendering engine primarily designed for animation and visual effects.
appleseed implements a modern workflow based on path tracing that enables artifact-free, single pass rendering with very little technical tuning.
It is simultaneously capable of strictly unbiased rendering when total accuracy matters, and biased rendering when artistic freedom and shorter rendering time are paramount.
[video=youtube_share;ISruC6rBkrM]https://youtu.be/ISruC6rBkrM[/video]
Yes! Love MagicaVoxel. 
Maybe the more funny excentric classic 2D Prog!
https://www.sumopaint.com (free online : you must have Flash Player (free) installed ! 
[video=youtube_share;SKZcf2PmYiU]https://youtu.be/SKZcf2PmYiU[/video]
Create your object in official Lego Designer (free)
Export it as “.ldr” format
Launch LeoCad (free)
Open your “.ldr” object
Save as Waterfront “.OBJ” format
Reload it with some plugins by Tig free or Thomthom free inside SketchUp Make 2017! (free)
Et voilà! 
Of course work like a cham inside ZBRUSH !!!
Ps You can create your object directly in Leo Cad if you prefere win a step! 
Here the more simple Lego brick with the big “3 steps race”! (Lego Designer -> Leo Cad -> SketchUp)
It will be trivial to make a Scale, any CleanUp and any texturing!
Have fun Lego Su party!
(or Lego ZBrush party !
Of course it’s the real Brick!!!
[video=youtube_share;X4c7Q0W4cDI]https://youtu.be/X4c7Q0W4cDI[/video]
… the Notice(s) of Construction
(for English version Click the flag up right corner page)
Can be useful! 
and some pieces in direct downloading!
For crazzy textures the free SumoPaint online is some sufficient! https://www.sumopaint.com/home/#app
(Flash Player must be installed)
Free SKetchUp Make 2017 : https://www.sketchup.com/fr/download/all#fr
Free Real Time render SimLab Composer Lite :
http://www.simlab-soft.com/3d-products/simlab-composer-lite.aspx (maxi 1920 *1080)
Of course ZBrush can also be used!
One free unlimited license for everybody.
[video=youtube_share;_AWd380dL_Y]https://youtu.be/_AWd380dL_Y[/video]
UV Mapping By Carnegie Mellon University
https://geometrycollective.github.io/boundary-first-flattening/
3D game engine/interactive 3D application
Don’t play the games if you have some modeling to do!
Click on “Vimeo” (right corner bottom) for have the programs’ links!
[video=vimeo;250171571]https://vimeo.cksom/250171571[/video]