Viewer for PDF images

[Salmon]

There is also a pretty easy Julia workaround, at least with CairoMakie:

Generate test plots

let 
    mkpath("OldFigs")
    mkpath("NewFigs")
    x = LinRange(0,2pi,100)
    funcs = (sin, cos, exp)
    for f in funcs
        fig = Figure(resolution = 350 .*(2.,1.3),fontsize = 20)
        ax = Axis(fig[1,1])
        lines!(ax,x,f.(x),)
        save("OldFigs/$(string(f)).pdf",current_figure())
    end

    for f in funcs
        fig = Figure(resolution = 350 .*(2.,1.3),fontsize = 20)
        ax = Axis(fig[1,1])
        lines!(ax,x,f.(x/2),)
        save("NewFigs/$(string(f)).pdf",current_figure())
    end
end

# This is the actual function that makes the comparison plot
using CairoMakie, FileIO, ImageMagick #ImageMagick seems to be neccessary for pdfs

function PicturesComparison(OldPath,NewPath)
    files1 = readdir(OldPath)
    files2 = readdir(NewPath)
    
    names = files1 ∩ files2

    fig = Figure(resolution = 800 .*(1,0.4*length(names)))

    axkwargs = (;
    xticklabelsvisible = false,
    xticksvisible = false,
    yticklabelsvisible = false,
    yticksvisible = false,
    spinewidth = 0.,
    xgridvisible = false,
    ygridvisible = false,
    aspect = DataAspect(),
    )
    OldAx = [Axis(fig[i,1],title = n;axkwargs...) for (i,n) in enumerate(names)]
    NewAx = [Axis(fig[i,2];axkwargs...) for (i,n) in enumerate(names)]


    for (i,n) in enumerate(names)
        for (j,p) in enumerate((OldPath,NewPath))
            img = rotr90(load(joinpath(p,n)))
            ax = [OldAx,NewAx][j][i]
            image!(ax,img)
        end
    end

    fig
end
PicturesComparison("OldFigs","NewFigs")

This produces the plot